1892.] Geology and Paleontology. 845 
can be no doubt. The genera with divided cervical ribs are Plesio- 
saurus, Eretmosaurus, Rhomaleosaurus and Pliosaurus. Those with 
simple cervical ribs are Polyptychoden, Polycotylus, Cimoliasaurus, 
Stereosaurus, Mauisaurus, Elasmosaurus, Trinacromerum, Colymbo- 
saurus, Muraenosaurus, Cryptoclidus. Thaumatosaurus he thinks is 
identical with Pliosaurus. 
Dana on the Huronian System.—In the Amer. Journ. Sci. 
Arts, Prof. Dana makes some rational observations on the recent 
proposition of certain members of the U. S. Geological Survey to add 
a fifth division to the geological system of time under the name of the 
Algonkian era. He says: “The Algonkian (or Agnotozoic) beds 
belong either to the Archean or to the Paleozoic. The Archean divis- 
ion of geological time is of the same category with the Paleozoic, Mes- 
ozoic and Cenozoic; all are grand divisions based on the progress of 
life, and they include together its complete range. There is no room 
for another grand division between Archean and Paleozoic any more 
than for one between Paleozoic and Mesozoic. The so-called Algon- 
kian is not above Cambrian in grade, it being based on series of rocks. 
Its true biological relations are in doubt, because fossils representing 
the supposed life of the period are unknown or imperfectly so. The 
discovery in any rocks so-called, of Trilobites, Crustaceans, Molluses, 
Brachiopods or Crinoids, whatever the species, would entitle such rocks 
to a place in the Paleozoic, and either within the Cambrian group or 
below it. Walcott has already reported such fossils from the beds at 
the bottom of the Colorado canyon referred by him to the Algon- 
kian, namely : besides a Stromatopoid, a small Patella-like or Discina- 
like shell, a fragment of a Trilobite and a small Hyolithes, forms 
which make the beds Paleozoic beyond question” (p. 460, June No., 
1892). 
Geological News.—Mr. Whitman Cross, in a late number of the 
Amer. Journ. Sci. Arts, endeavors to set forth the state of our knowl- 
edge of the stratigraphy and incidentally paleontology of the Laramie 
formation. He thinks it probable that the alleged Laramie includes 
several formations, which are distinguished by unconformity end 
lithological diversity. He gives a very thorough review of the litera- 
ture of the subject. 
—The appropriation for the U.S. Geological Survey was much reduced 
by the last Congress. Nearly forty members of the present force will 
be asked to resign. Washington dispatches to the newspaper press 
