Geology and Natural History. 319 



from the Austin Chalk of Shnmard (Niobrara of M. & H.) as the 

 author asserts, all of these forms came from an entirely different 

 and lower horizon, separated by four distinct subfaunas, a com- 

 plete stratigraphic and paleontologic non-conformity, and four 

 hundred feet of strata below that horizon, and hence the deduc- 

 tions and correlations of Dr. Roemer are unfounded. The twenty- 

 one species mentioned, together with a half dozen or so in the 

 writer's possession, which escaped Dr. Roemer's attention, are 

 mostly non-criterional genera (except the aberrant bivalves), 

 which range in European terranes from Jurassic to present, but 

 which are especially numerous in the upper Jurassic and Lower 

 Cretaceous, all being found in the European Neocomian, espe- 

 cially the peculiar aberrant bivalves and the Nerineas — the va- 

 rieties described of the latter having especial Jurassic affinities. 

 Hence, Dr. Roemer's assignment of this fauna to the Upper Turo- 

 nian horizon is not based upon sufficient evidence either strati- 

 graphical or paleontological. They belong to the Hippurites Lime- 

 stone of Shumard, whose stratigraphic place as given in my section 

 is in the middle of the Lower American Cretaceous. K. t. hill. 



5. Shall we teach Geology f A discussion on the proper plan of 

 Geology in modern education / by Alexander Winchell. 217 

 pages, 12mo. — Prof. Winchell makes in this volume a strong 

 plea for the study of geology in schools and higher institutions 

 of learning, treating at length of its educational value as com- 

 pared with other subjects of study, its ethical influence, and the 

 bearing of its developments on modern civilization. His large ex- 

 perience enables him to bring forward in illustration, a wide 

 range of facts with regard to the science, and the best methods 

 of instruction. 



6. The Descending Water-current in Plants and its Physi- 

 ological Significance. J. Wiesner (Botanische Zeitung, Jan. 

 4, 1889). — In an earlier paper the author gave an account of the 

 supposed existence of a downward movement of water in the 

 branches and stems of plants. In the present communication he 

 points out the bearing of his discovery upon the coordination of 

 the various organs. Experimental proof of the existence of the 

 descending current of water is thought by the author to be 

 afforded in the following way. When a severed leafy shoot of 

 fresh grape-vine is immersed in water, the tissues are more tur- 

 gescent than before they are covered by water, indicating 

 absorption through the epidermis. If, now, the middle portion 

 of such a shoot is lifted into the ah', so that transpiration can go 

 on rapidly, the upper part of the shoot, which is still immersed, 

 will soon become wilted, showing that it is furnishing water to 

 the parts lower down the stem. Assuming that this experiment 

 shows the existence of a downward current, the author passes at 

 once to the application of this fact to the explanation of the 

 development of various parts. He believes, for instance, that 

 the opening of many flowers and flower-clusters is caused largely 

 by the movement of water in the branch or stem, and especially 



