Geology and Mineralogy. 233 



level of the stratified sand and gravel. The glacial stria- have a 

 southeast directum. A lower secondary ridge, the last crossed bv 

 the highway before Ekaterinburg, has many parallel range* <>f 

 immense bowlders. — Nature, Feb. 1. 



10. Trilobites.— Mr. G. D. Walcott, of Trenton Falls, New 

 York, a famous place for Trenton Trilobites, has succeeded in 

 finding many specimens that illustrate directly, or by sections, 

 the nature of some of the interior organs of the species. Ik- 

 has detected in many individuals axial appendages beneath the 



aoh segment of the 

 thorax and pygidium and the three posterior of the head have 

 ;1 pah; 1> ueath the axial processes. Those of the thorax and 

 pygidium appear to be short cylindrical supports for swimming 

 appendages or rudimentarv ambulatory organs; and those of the 

 ll, -a<l present an obscurely jointed structure. In the same species 

 there are "obliquely incfin. d bars bem tth tin pleural lobes, near 

 the union with the free pleurae," which he regards as connected 

 with branchial appendages" In nine of his sections he has counted 

 43 such appendages. The bars appear to have had a fleshy or 

 i support. The greatest number of bars seen in position 

 belonging to one appendage is fourteen ; it is rare to find them in 

 position. Longitudinal sections at the union of the pleural lobes 

 and free pleurae show the branchial .appendages as rows of dots, 

 varying from square to oblong in shape. In Calymeue tenaria 

 these appendages are essentia Ih tin -ame as in Cer'/unas. Nume- 

 rous central longitudinal sections of Ceraurus show the mem- 

 brane covering ' the visceral cavity beneath the axial lobe. 

 Acidaspis Trentonensis is closely like the Ceraurus in the struc- 

 ture of its ventral surface. 



The ventral surface in Asaphm platycephalus appears to have 

 been strengthened bv ted the double row of 



appendages on each side of the central axis. These are the arches 

 which were suspected to be legs by Billings. 



These notes are from a brief paper by Mr. Walcott, from the 

 :"'^ Report of the New York State Museum, printed in Septem- 

 !j " lagt, in advance of its publication. 



11. Geology and Paleontology of the Argentine Republic. II. 

 Paleontologies] part: .ud division, on the Rhetian plants and 



mains of the Provinces of La Kioja. San Juan, and Men- 

 «oza, by Dr. H. B. Geixitz. 16 pp. 4to, with two plates.— The 



Xcies here described bv Dr. Geii u an th« ti>h, ^unionotus 

 ndozaensis Gein., the Grustacean, Estheria Mangaliensis Jones, 

 a species first described from Mangali of Nagpur in Central India; 

 1111,1 among the plants there are tin l'Vrn>, Thlm, \ldki cra*d- 



- 

 - 

 described originally from I. Bon ^^ En g" 



la H Tmniopterls Mareyesiaea Gein.; the Cycad, PterophyUum 

 A »- Jodk. Sct.— Third Skbies, Vol. XIII, No. 75.-Mabch, 1877. 



