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tain region of Colorado, and comes to the following conclusions as to their 
chronology. In very early times there was in Colorado, Archaean land rising 
above the Palaeozoic sea. As the Carboniferous age progressed this land 
diminished by encroachments of the sea, due to subsidence of the land, 
which persisted through the Triassic, Jurassic, and Cretaceous periods into the 
early Tertiary. At the close of the Lignitic Tertiary period, there was a physi- 
cal break, followed, at least locally, by a subsidence and subsequently by an 
elevation after the deposition of the Miocene strata. The elevation of the 
Rocky Mountains as now seen in Colorado is the result of an elevation com- 
mencing in early Tertiary time, when there was probably great volcanic 
activity in the region, and continuing through the Tertiary period, accelerated 
perhaps at the close of the Lignitic, and after the deposition of the Lower 
Miocene strata. Dr. Peale thinks that this elevation is still going on. The 
great elevation ascribed to the Colorado region in Palaeozoic times is con- 
sidered by Dr. Peale to be confirmatory of the generalization of Dr. New- 
berry, to the effect that the outlines of the western part of the North 
American continent were already indicated at that early period in the history 
of the earth. 
A New Algerian Fossil Hippopotamus. — According to M. Gaudry (“Bull. 
Soc. Geol. de France,” February, 1877), the remains of anew and interesting 
species of Hippopotamus occur in a breccia at Bone, in Algeria. The fossil 
bones indicate a species in which the dentition is less different from that of the 
pig type than that of the ordinary Hippopotami. It differs from the existing 
Hippopotamus (H. amphibius ) by the presence of six incisors instead of four 
in the lower jaw, the nearly equal size of the incisors, the thicker, unchan- 
nelled, and more clearly marked enamel of these teeth, and the presence of 
only fine striae, instead of strong channels, in the canines. By the number 
of incisors the Hippopotamus from Bone would belong to the genus Hexa- 
protodon of Falconer and Cautley, which is represented by three Indian 
species (FT. sivalensis, iravaticus, and namadicus ) ; but, from the fact that 
the teeth of the Algerian species present certain peculiarities not noticed 
by Falconer in those of the eastern deposits, M. Gaudry regards the 
former as a distinct species under the name of Hippopotamus ( Hexapro - 
todon) hipponensis. M. Pomel thinks that the deposit in which these 
remains occur is of Quaternary age. 
Hydractinia, Parkeria, and Stromatopora. — Mr. H. J. Carter publishes in 
the “Annals and Magazine of Natural History ” for January, an elaborate 
paper, the object of which is to prove that the curious fossils forming the 
genera Parkeria and Stromatopora , and probably some others, are really 
the remains of Hydrozoa allied to Hydractinia. He indicates the characters 
of the Hydractinia, and describes a new calcareous form, H. calcar ea, from 
the Guinea coast, where it is found incrusting small univalve shells tenanted 
by hermit crabs, and indicates its close approach to the species (AT. pliocena ) 
described in 1872 by Professor Allman from the Coralline Crag of Suffolk. 
He also describes a species with a siliceous skeleton (FT. Vicaryi) from the 
Upper Greensand of Haldon Hill. The Parkerice, spherical or spheroidal 
bodies found in the Cambridge Greensand, have been described by Dr. 
Carpenter as Foraminifera, on the ground of their chambered structure, 
which starts, as in many Foraminifera, from a peculiarly chambered nucleus. 
