Percival's account of his methods of procedure are not without interest. He says:"

I had twice surveyed the whole State on a regular plan of sections from east to west, reducing the intervals in the last survey to an average distance of 2 miles, thus passing along one side of each of the nearly 5,000 square miles of the State. * I had examined all objects of geological interest, particularly the rocks and those including minerals, with minute attention. I scarcely passed a ledge or point of rock without particular examination. I had completed 11 manuscript volumes, amounting to nearly 1,500 pages, very finely written in abbreviation. I had collected specimens from at least 8,000 localities, according to a very reduced calculation from actual enumeration of one town, and several specimens from each locality, each specimen intended to illustrate something peculiar and noticed in my notes; all my specimens marked on the papers enclosing them and checked in my notebooks, so that I know their precise locality and could again trace them to the spot where I found them. In all these researches, from the commencement, I had had in view the determination of the geological system of the rocks of the State. All these researches had been a continued process, not only of particular examination, but of comparison and reflection, all tending to the determination of the great system. I say with the confidence of conviction-of that conviction which arises from long-continued devotion to the subject-that I have determined in my mind the system of arrangement; that it is a new system with me, the result of my own unassisted observation, one which I have not traced in my reading, and one which I believe to be of the highest importance, not only to science, but for economical purposes. Besides this more general plan of the survey, I had especially explored and traced out the trap, both connected with the primary and secondary, and determined a new and important system of arrangement, apparently applicable to both, and one, too, of which I have found no traces in my reading.

Up to the session of 1840, I had employed five years on the survey and had received $3,000, averaging $600 per annum, out of which I had defrayed all expenses, traveling expenses included. * I was then required to prepare

*

a report, cut off from all resources, deprived of that pittance of $500, which I might have secured two years before almost without additional labor, if I had regarded my own interests only.

According to Professor Dana,' Percival, on entering upon his duties, saw before him two great problems:

*

First, the character and origin of the trap ridges of the State, such as East and West Rocks near New Haven, the Hanging Hills of Meriden, and other similar heights to the north and south, and, secondly, the characters and origin of the granitic series of rocks which prevail through all the rest of the State.

Percival's observations proved:

that there had been not one long-continuous fracture through the State from New Haven to the regions of Mt. Tom and beyond, for the injection of liquid trap rock, but instead, a series of openings along a common line, and that there were several such lines running a nearly parallel course over a broad region of country. He also found that the ridges which compose a range do not always lie directly in the same line, but that often the parts which follow one

1 Life and Letters of J. G. Percival, by J. H. Wood.

another are successively to the east of one another, or to the west, en echelon (as the French style it); and, further, that the parts of the component ridges of a range were often curved, or a succession of curving lines. He discovered, too, that in the region of the Meriden Hanging Hills the trap ridges take a singular east and west bend across the great central valley of the State-a course wholly at variance with the old notions.

The work which he accomplished was, in the first place, an extended topographical survey of this portion of the State, and, secondly, a thorough examination of the structure and relations of the trap ridges, with also those of the associated sandstone. And it brought out, as its grand result, a system of general truths with regard to the fractures of the earth's crust, which, as geologists are beginning to see, are the very same that are fundamental in the constitution of mountain chains. For this combination of many approximately parallel lines of ranges in one system, the composite structure of the several ranges and the en echelon, or advancing and retreating arrangement of the successive ridges of a range, are common features of mountain chains. The earth's great mountains and the trap ranges of central New England are results of subterranean forces acting upon the earth's crust according to common laws. The State of Connecticut, through the mind and labors of Percival, has contributed the best and fullest exemplification of the laws yet obtained, and thus prepared the way for a correct understanding of the great features of the globe.

Percival pursued his second subject, that of the granitic rocks, with similar fidelity, and mapped out with care the several formations. * * * His labors were not without practical results, for he was the first to explain correctly the origin of the iron-ore beds of Kent and similar beds in the Green Mountain range.1

The receipt of this report gave rise to the following resolution:

At the general assembly of the State of Connecticut, holden at New Haven in said State, on the first Wednesday of May, in the year of our Lord one thousand eight hundred and forty-two.

Resolved by this assembly, That not less than 1,000 copies of Dr. James G. Percival's report on the geology of Connecticut be published under the superintendence of the author, and that a sum not exceeding $1,500 be appropriated to defray the expenses of printing and superintending, and that the controller of the public accounts be hereby authorized to draw an order on the treasurer for such sum, not exceeding $1,500, to be paid out of money not otherwise appropriated; and his excellency the governor and Hon. Henry W. Edwards are hereby appointed commissioners to see the object of this resolution effected.

And be it further resolved, That the commissioners before named be authorized to cause the copyright of the said report to be secured to the State and to permit any additional number of copies to be published and disposed of in such

1 Messrs. Gregory and Robinson, of the present survey (1907), in like manner render appreciative testimony: " Percival's Report on the Geology of Connecticut is not a readable book; it does not contain theories and inferences and bits of lively description, but merely dry facts grouped geographically. It is about the last book which a poet, one of the most celebrated of his time, would be expected to write. Accuracy and keenness of observation and distinctness of representation are, however, prime requisites for lasting scientific work, and in these qualities Percival excelled. The more the modern geologist becomes familiar with the involved structures and exasperating variations found within the metamorphic rocks of the State, the more respect and admiration he has for Percival's discrimination and skill of delineation. It is doubtful if ever a more accurate discrimination of the various members of a complicated series of crystalline rocks on field evidence alone was ever accomplished."

manner and on such terms as they may deem proper, for the benefit of the author: Provided, That no additional expense be thereby incurred by the State over and above the sum of $1,500 aforesaid.

Expense. The resolution establishing the survey makes no references to expenses or appropriations. Nothing is stated as to amount paid Professor Shepard for services, but in the bill of 1837, $500 was appropriated for the publication of his report. Percival, in his lamentations, writes of having received $3,000 in salary, and, as above noted, $1,500 was appropriated for publication. The expense of the survey can then be placed at $5,000, exclusive of Professor Shepard's salary, which it is safe to say was small, if indeed he received anything.

By an act approved June 3, 1903, a second survey, geological and natural history, was established under control of a board of commissioners, with Prof. William North Rice, superintendent. This survey is still in progress.1

DELAWARE.2

The first and only systematic attempt at a geological survey of Delaware was made in 1837, in virtue of an act of the legislature, of which the following is a transcript:

An act to provide for a geological and mineralogical survey of this State. SECTION 1. Be it enacted by the senate and house of representatives of the State of Delaware in general assembly met, That Thomas Stockton, of New Castle County; Jonathan Jenkins, of Kent County; and Dr. Henry F. Hall, of Sussex County, be and they are hereby appointed commissioners to procure to be made a geological and mineralogical survey of this State. And it shall be the duty of the said commissioners, as soon as practicable after the passage of this act, to appoint a State geologist of talents, integrity, and suitable scientific and practical knowledge of his profession, who shall also be a scientific and practical mineralogist.

SEC. 2. And it shall be the duty of the said State geologist immediately to commence and carry on with as much expedition and despatch as may be consistent with minuteness and accuracy, a geological and mineralogical survey of the State, with a view to determine the order, succession, arrangement, relative position, and the dip or inclination, and also the comparative magnitude of the several strata, or geological formations, within the State, and to discover and examine all beds and deposits of ores, coals, clays, marls, and such other mineral substances as may be deemed useful or valuable, together with such other duties as may be necessary to make a full and complete geological and mineralogical survey of this State.

SEC. 3. And it shall be further the duty of the said State geologist, on or before the first day of January in each and every year during the time necessarily occupied by the survey, to make a report of the progress of the survey, accompanied with such maps, drawings, and specimens as may be necessary

1 See Bulletin 465, U. S. Geological Survey, 1911.

2 Compiled in part from manuscript, by J. C. Booth.