168 ARTESIAN WELLS ON THE ATLANTIC COAST. [bull. 138. 
Ft. In. 
202 more clayey than 194 feet; fragments of Venus, etc. 
204 more clayey than 194 feet ; fragments of Venus, etc. 
208 more clayey than 194 feet ; fragments of Venus, etc., with Perna, 
Venus, etc. 
390 tenacious gray clay with shelly matter. 
400 gray sandy clay ; Artemse, Venus, etc. 
430 yellowish sandy clay. 
555 light clay, gray brown in color; Foraminiferse. 
558 infusorial earth containing many species. 
576 Miocene down to about this depth. 
574 cetacean bone. 
577 0. r concretions of sand, marl, and shells, composed of loam sand, 
little pieces of milky and smoky and sometimes rose quartz, 
often subangular; between 577 and 583 feet is probably the 
base of the Miocene ; between 580 and 590 feet shark's teeth 
and Galeocerda lateralis. 
583 sandy clay, brownish. 
590 very sandy clay ; about 5 per cent sand ; shark's teeth. 
604 brownish-gray, sandy clay. 
628 brownish-gray, sandy clay ; less sand. 
640 greenish gray, sandy. 
670 lightest gray clay. 
699 brownish-gray, sandy clay ; less sand than 604 feet ; same in bed 
as 628 feet. 
784 brownish-gray, sandy clay ; same as 604 feet. 
815 gray sandy clay. 
835 very coarse sand. 
853 conglomerate of clay, sand, and pebbles. 
863 rather fine clay with a little sand. 
865 rather fine clay with a little sand. 
870 coarse sandy clay, brownish or reddish blotches. 
877 clay, embedding fragments of granite. 
885 gray clay with occasional fragments of coarse sand. 
890 gray clay with occasional fragments of coarse sand. 
900 clay and sand in layers, with some coarse pebbles and reddish 
blotches. 
901 reddish mottled clay with quartz pebbles. 
902 reddish mottled clay with coarse sand. 
903 reddish mottled clay with coarse sand. 
907 total depth of boring below parade ground. 
This table does -not give tlie thickness of the beds, which is greatly 
to be regretted. The suggestion of Professor Rogers that the base of 
the Miocene (Chesapeake) is between 577 and 583 feet was based on the 
idea that the infusorial beds here characterized the very base of the 
formation and that the occurrence of shark's teeth indicated the under- 
lying Eocene (Pamunkey) deposits. It was also suggested that the lower 
beds, from perhaps 835 feet to the bottom, may possibly be Jurasso- 
Gretaceous, or the Potomac formation of later writers. This was based 
on the presence of reddish mottlings and coarse sand streaks in the 
lowest clays. 
In 1880 Professor Fontaine, of the University of Virginia, examined 
the old records of the borings, and an account of these, which lie has 
