264 



SCIENCE. 



[N. S. Vol. XI. No. 268. 



tinguish them from the Supra Patagouian beds. 

 This aloue is a most important point, since it 

 gives us a definite base from which to start in a 

 comparative study of the Tertiary formations of 

 Patagonia, as they are understood by Drs. von 

 Iheriug and Ameghino. It is to be hoped that 

 the latter author will also, in the no distant 

 future, realize the importance of giving at least 

 some one definite locality at which each of the 

 various geological horizons (Mesozoic and Ter- 

 tiary) that have been named by him at various 

 times may be found and studied. It is alone by 

 such frankness, which should characterize the 

 work of naturalists everywhere, that we shall 

 be able the more easily to arrive at a true solu- 

 tion of the age and relations of the various geo- 

 logical formations of Patagonia. 



According to Dr. von Ihering (see page 4 of 

 his paper), the fossil shells of the Santa Cruz 

 (Supra Patagouian) beds are usually enclosed iu 

 a soft, sandy matrix, while those of the Patago- 

 nian beds are firmly imbedded in very hard 

 clay stones. Dr. von Ihering does not contend 

 that these conditions are absolute throughout 

 the two series, but that the former prevails in 

 the upper series while the latter predominates 

 in the lower. He also finds the faunas of the 

 two deposits to be quite distinct. On pages 6 

 and 7 he gives a list of 67 species as belonging 

 to the Patagouian beds. He finds only 16 of 

 these 67 species in the Santa Cruz (Supra Pata- 

 gouian) beds. On page 38 he gives a number 

 of genera and species which according to him 

 are characteristic of the Santa Cruz (Supra Pa- 

 tagouian) beds. 



Regarding the lithologic characters given by 

 Dr. von Ihering, it should of course be remem- 

 bered that he has himself never visited Pata- 

 gonia, and has therefore to rely upon the nature 

 of the matrix adhering to the fossils and the 

 reports of Mr. Bicego, whose observations in 

 southern Patagonia have been limited to the 

 region about the mouth of the Santa Cruz 

 river. But even in that locality Mr. Bicego 

 certainly could not have failed to observe that 

 the lithological conditions given by Dr. von Iher- 

 ing, as prevailing in the Patagouian beds, are 

 in reality, of extremely limited extent when 

 compared with the entire thickness of fossil- 

 bearing rocks at this locality. There are, as 



Dr. von Ihering says, many instances of hard 

 clay-stones or other concretions literally filled 

 with the shells of mollusca, and occasionally a 

 stratum of hard sandstone, which is also fossil- 

 liferous. The superior resistance which such 

 materials offer to erosion are apt to mislead the 

 not too careful collector as to their relative im- 

 portance, and with such material at hand, and 

 to be had only for the picking up, he is likely to 

 overlook many of the real gems which will 

 richly reward the collector if he turns to the 

 several hundred feet of soft sand and claj^s 

 and examines them in situ. On weathering 

 away, however, the usually soft delicate shells 

 are reduced to powder and rendered worth- 

 less. If Mr. Bicego had occasion to examine 

 the bluffs along the south side of the Santa 

 Cruz river, between the village of Santa Cruz 

 and Direction hill at the mouth of the river, 

 he must have seen numerous shell layers in the 

 soft crumbling sands and clays, which consti- 

 tute by far the greater portion of the 350 feet 

 of sediment exposed in the bluffs. A notable 

 example of this is to be seen in the bluflF of the 

 river about one and a-half miles above Direction 

 hill and just above where formerly stood the 

 temporary observatory erected a few years ago 

 by the United States Steamer Brooklyn (?). 

 At this point the bluffs rise directly from the 

 river and there is a continuous stratum of loose 

 sand, filled with shells. This stratum is about 

 six inches thick aud a quarter of a mile in 

 length. It is located at a height of only five 

 to ten feet above high water and can scarcely 

 fail to attract the attention of anyone passing 

 along the foot of the cliff. At various altitudes 

 above it, other similar shell-bearing layers may 

 be seen in the same bluff. At Direction hill 

 and along the coast to the southward are many 

 other strata of soft materials rich in fossils, 

 while if any one will take the trouble at low 

 tide to walk out over the surface of the beach 

 he will frequently see the soft tosca literally 

 filled with fossil shells. In one soft stratum 

 near the mouth of the river the writer 

 found a bed about eight inches thick and 20 

 to 30 feet in length, composed almost entirely 

 of the shells of Slruthiolaria ornata, which 

 according to von Ihering is characteristic 

 of the Patagouian beds, mingled with a few 



