---+-------------+------------+------------------------------+---------- | SYSTEM. | GROUP. | STRATA. |THICKNESS. ---+-------------+------------+------------------------------+---------- | | | | FEET. 1 | Drift. | Alluvial | Clay, sand, and gravel. | 123 | | drift. | | | | | | | { | Base of | | 2 | Devonian. { | Hamilton. | Dark bituminous shale. | 15 | { | Helderberg.| Dark and gray limestone with | | | | bands of chert. | | | | | | { | Niagara. | Sandy above, darker and | 626 3 | Upper { | | argillaceous below. | 4 | Silurian. { | Clinton. | Red, brown, and gray shales | 162 | { | | and marls. | | | | | | { | Hudson | | 5 |Lower { | Trenton. | Greenish calcareous shale. | 1058 6 |Silurian. { |Calciferous.| Light drab sandy magnesian | 475 7 | { | | limestones. | | { | Potsdam. | White sand-rock, calcareous. | 316 ---+-------------+------------+------------------------------+---------- Temperature of well at bottom, 88 degrees, being uniform for 90 feet, at 53 degrees, will make an increase of one degree for every additional 71 feet. It was the opinion of Prof. Newberry, that, if water was successfully struck, it would be of a saline character. Dubuque, Iowa, is supplied by a spring accidentally struck while tunneling in a neighboring drift. At the upper basin of the Thames River there are seven springs, whose capacity is estimated at 32,000,000 gallons daily. Liverpool, England, has four wells, with a combined capacity of 6,000,000 gallons daily. Birmingham, England, has four wells, from which the water company derives 8,000,000 gallons daily. Washington has over 400 wells, and Cincinnati about 300, nine of which are artesian, that were bored by private enterprise. The deepest well in the world is near Berlin--4194 feet deep without piercing the salt formation. WELL BORING. The art of boring into the earth was practiced by the Chinese 2,000 years ago, the feature of their system being the percussive action of a tool suspended by a flexible rope.