956 The American Naturalist. [October, 
In America there are probably about a dozen valid species of 
Naticopsis, the others described as such being identical with forms 
previously known. Patica littonana Hall, from the Warsaw limestone, 
apparently belongs to the globose group of Soleniscus, and will there- 
fore stand as S. Zittonanus. For Isonema depressa M. and W. it is 
proposed to substitute the name Naticopsis linearis. (C. R. Keyes, 
Am. Geol., October, 1889.) 
H. A. Wasmuth, in the Am. Geol., May, 1888, closes a description 
of the Pittsburgh Coal Bed with a reference to the Devonian forma- 
tions, reservoirs of gas and oil, that underlie it. Naturally, the 
greatest amount of gas should be found on the higher elevations (an- 
ticlinals), and of oil in the deeper portions of synclinals of the 
Devonian formations; but as this theory is refuted by geologists of 
reputation, there remains the influence of disconnections and disloca- 
tions of the oil- and gas-bearing strata by clay veins, etc., to explain 
the productivity of the oil- and gas-wells of Pennsylvania. 
Jurassic.—R. Lydekker announces the discovery of a new croco- 
dile, Suchodus durobrivensis, from the Oxford clay of Peterborough. 
(Quar. Jour. Geol. Soc., May, 1890.) 
A. Smith Woodward notes three small Ichthyolites from the Paper 
Shales of Wigston, referable to a small species of Pholidophorus, 
P. nitidus Egerton. (Trans. Leicester Lit. and Philosoph. Soc., April, 
1889.) 
R. Lydekker has referred two vertebr&, one from the Wealden of 
Cuckfield, the other from the Wealden of Brook, to Pleurocelus 
valdensis. Their especial interest lies in the circumstance that, in con- 
nection with some opisthoccelous teeth, they afford absolutely conclu- 
sive evidence of the occurrence in the English Wealden of 4 
diminutive opisthoccelous Dinosaur, which was the contemporary 
of the huge Ornithopsis, and the still more gigantic Pelorosaurus. 
(Quar. Journ. Geol. Soc., May, 1890.) 
Cretaceous.—According to Robert T. Hill (Am. Geol., 1889) 
the Cretaceous exposures of the Texas-Arkansas region record two 
subsidences. Of the total sediments of the Lower, aggregating over 
2,000 feet, 1,500 are limestone, all but 100 feet of which are of foram- 
iniferal origin. Of the 700 feet of limestone of the Upper Cretaceous 
formation of Texas 600 feet are of foraminiferal origin. 
J. S. Newberry (Trans. N. Y. Acad. Sci., Vol. IX.) gives the fol- 
lowing reasons for considering the Laramie the upper member of the 
