weeks.] PALEONTOLOGY, PETROLOGY, AND MINERALOGY, 1894. 85 
508 Shaler (Nathaniel Southgate). On the distribution of earthquakes 
in the United States since the close of the Glacial period. 
Bost. Soc. Nat. Hist., Proc, vol. xxvi, pp. 246-256. 
Abstract : Am. Geol., vol. xiv, pp. 396-397 (i p.). 
Discusses the evidences of earthquake shocks indicated by the action 
of the ocean wave in moving poised blocks and unstable topographic 
forms along coast lines and by the overturning of unstable bodies on 
land. Gives the results of observations of these phenomena on the 
coast lines of the United States. 
508a The origin and nature of soils. 
Am. Geol., vol. xiv, pp. 114-115 (^ p. ). 
Noticed in Bibliography and Index for 1892 and 1893. 
508/> Sherborn (Charles Davies). An index to the genera and species 
of Foraminifera. 
Smith. Inst., Misc. Coll., vol. xxxvii, pt. i (a to uon) ii+240 pp. 
509 Siebenthal (0. E.). The geology of Dallas County, Ark. 
Ark. Geol. Sum, Ann Rept., 1891, vol. ii, pp. 279-318. 
Describes the topographic and geologic features of the county and 
the occurrence of potter's clay. 
510 Simonds (Frederick W.). [Glacial geology of Lake Cayuga and 
vicinity, New York.] 
Am. Geol., vol. xiv, pp. 58-62 (correspondence). 
Reviews the paper by R. S. Tarr on Lake Cayuga, a rock basin. 
511 and Hopkins (T. C). The geology of Benton County, Ark. 
Ark. Geol. Surv., Ann. Rept., 1891, vol. ii, pp. 1-75. 
Describes the topographic features of the county, the drainage and 
springs, the lithologic character and distribution of the Silurian, 
Devonian, and Carboniferous formations, and the character and occur- 
rence of economic products. 
512 Simpson (Charles T.). On some fossil unios and other fresh- water 
shells from the drift at Toronto, Canada; with a review of 
the distribution of the Unionidre of northeastern North 
America. 
U. S. Nat. Mus., Proc, vol. xvi, pp. 591-595. 
Gives a list of the fossils collected and discusses the geologic and 
geographic distribution of the Unionida' in northeastern North 
America. 
513 Simpson (George B.). A discussion of the different genera of 
Fenestellid;c. 
N. Y. State Mus., 47th Ann. Rept., pp. 881-921. 
Discusses the relations of the genera and includes remarks on the 
various genera of Fenestellidrc. 
514 Glossary and explanations of specific names of Bryozoa and 
corals described in volume vi, Paleontology of New York, 
and other reports. 
N. Y. State Mus., 47th Ann. Rept., pp. 925-941. 
