170 Tertiary. 



The deposits in which these terraces have been worn consist o-t" clay, 

 containing marine shells, among which are Tellina groenlandica, T. 

 calcarea, Saxicava rugusa, Nucula, Venus, Mytilns, and Balanas. 

 These shells were found as high as 390 feet above the ba}^ At Little 

 Malbaie there are six terraces, plainly distinguishable, one above 

 another. 



T. A. Convad* described, from the Eocene of Georgia, Mitra 

 georgiana, Catopygus conradi, now Cassidulus conradi, Holaster 

 mortoni, Nucleolites lyelli., Discoidea haldemani, and Gidarites 

 mortoni. Robert W. Gibbes described, from the Eocene of Ashley 

 river, Myliobates holmesi. And Zadock Thompsonf described, from 

 the drift in Vermont, exposed in excavating for the Rutland and 

 Burlington railroad, Delphinvs vermontanifs, now Beluga vermon- 

 tana. 



In 1851, Philip T. TysonJ described the Sacramento Valley as 

 a long prairie, occup3-ing the space between the flanks of the Sierra 

 Nevada and those of the Coast Range, closed in on the north by the 

 terminal spurs of the Cascade mountains, and on the south by the 

 iunction of the Coast Range with the Sierra Nevada. Its greatest 

 width is less than 60 miles, but it maintains a mean width of nearly 

 50 miles throughout almost its entire length. The surface strata are 

 not older than the Eocene or Miocene, and rest immediatelj^ upon the 

 metamorphic and hypogene rocks. 



Prof. James Robbg showed the direction of the Drift strise in New 

 Brunswick to be, generally, about 10 deg. W. of true north to 10 deg. 

 E. ot south, but that some strise have a direction N. 30 deg. E. Others 

 N. 45 deg. W., and still others east and west. 



T. T. Bouvejl described, from the Eocene of Georgia, Catopygu,s pa- 

 telliformis, now Cassidulus patelUformis, and Hemiaster conradi. 



In 1852, Mr. J. Evans^ explored that region of the Upper Missouri 

 country, lying high upon White river, called the " Mauvaises Terres^'' 

 or "Bad Lands." He said that from the high prairies, which rise in the 

 back, by a series of terraces or benches toward the spurs of the Rocky 

 Mountains, the traveler looks down into an extensive valle}^ that may 

 be said to constitute a world of its own, and which appears to have 

 been formed partly b}' an extensive vertical fault, and partly by the 

 long continued influence of the scooping action of denudation. 



* Jour. Acad. Nat. Sci., 2d ser., vol. ii. 



i Am. Jour. Sei. and Arts, 2d sor., vol. ix. 



\ Geo. and Ind. Resources of Cal. 



% Proe. Am. Ass. Ad. Sci., 4th Meeting. 



1 Proe. Bost. Soc. Nat. Hist., vol. iv. 



IT Geo. Sur., Wis., Iowa and Minn. 



