1881. ] Geology and Paleontology. 253 
form, possibly referable to this genus. 3. Cheirolepis. A beauti- 
fully preserved fossil fish, about a foot in length, which cannot 
oD , 
Sp 
sp. 6, Portion of the vertebral column of the above species o 
Tristichoporus shewing the neural and hemal spines and the 
processes which support the rays of the tail, also the two ischiatic 
bones with the metatarsals attached, which must have formed the 
bases of two enormously developed ventral fins. 
Tue MILtsTone Grit IN ENGLAND AND PENNSYLVANIA.—In the 
February number of the Amer. ¥ourn. Science, Mr. Chance, of 
the Geological Survey of Pennsylvania, calls attention to the 
remarkable parallelism between the stratification of the Millstone 
grit in Pennsylvania and England. He gives the following com- 
parative sectional tables from the reports of the two countries: 
Yorkshire. Pennsylvania. 
Rough rock. Homewood sandstone. 
Shales (sporadic coals). Mercer coal group. 
Second grit. Conoquenessing Upper sandstone. 
Shales (coal). , Quakertown coal, 
Third grit. 3 Conoquenessing Lower sandstone, 
Shales (coal). Sharon coal. 
‘Kinder Scout”’ grit. Sharon or Ohio Conglomerate. 
Over large areas this nomenclature is applicable to all vertical 
sections in both Yorkshire and Western Pennsylvania. The top 
and bottom sandstones are especially durable and constant, and 
form “key rocks” in both countries, for the determination of 
other horizons. 
pard of Philadelphia. 
Tne Stream-Tin Deposits oF Brrronc.—Dr. Martin of Leyden 
has determined the age of the Stream-tin deposits of Blitong (or 
Biliton), by means of an extensive series of Mod/usca obtained from 
it. They number sixty-one species, of which only two are cer- 
tainly new to science. The remainder are all recent species, €x- 
cepting a Cerithium, which has hitherto been only known from 
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