December 28, 1900.] 



SCIENCE. 



995 



free-moving support, and this in turn resting 

 on two wooden knife edges. The panto- 

 graph is fixed to the top of a table from 

 which a portion of the top has been removed. 

 Below this opening is a depressed shelf on 

 which is placed a tin box containing the 

 plastic clay, which is of a thickness corre- 

 sponding to the uniform base and the highest 

 point to be represented. Beginning at the 

 topmost contour the stylus traces the limits 

 of that elevation. Outside of the line traced 

 the clay maj' be removed to the first bench. 

 In the same way all the contours may be 

 followed by one arm of the pantograph and 

 traced in clay by the other. The result is 

 a rough representation of the shape of the 

 county in which the surface is composed of 

 a series of steps. These may be removed by 

 a modeling wire and the whole given artistic 

 life without changing the relative elevation 

 of the different parts. It has been found 

 possible to prepare this first relief model of 

 a quadrangle in a day's time. From this 

 it is possible to make the usual plaster 

 matrices and thence the plaster relief ac- 

 cording to the usual methods. The advan- 

 tage of the machine lies in the speed by 

 ■which the models may be produced and the 

 elimination of the personal equation in the 

 drawing of the heights. 



In a short but interesting paper on ' Cer- 

 tain Late Pleistocene Loams in New Jersey 

 and Adjacent States,' Professor R. D. Salis- 

 bury presented the results of his numerous 

 observations concerning the origin of cer- 

 tain recent loams found widely distributed 

 in that region. These had been examined 

 in hundreds of localities and found to be 

 generally more or less local in character. 

 Sections were exhibited showing its mode 

 of occurrence near Jamesburg, Princeton, 

 Trenton, Philadelphia, etc. The conclu- 

 sions arrived at from these various examina- 

 tions were that these loams are of marine 

 origin and represent deposits made during 

 a recent short period of submergence, which 



submergence in southeastern New Jersey 

 extended to a depth of not less than 200 

 feet. The work of Professor Salisbury is 

 the more interesting as it has an important 

 bearing on the results of the study of some- 

 what similar surface loams and sands fur- 

 ther south by Hilgard, McGee, Smith and 

 Holmes. 



In the paper on ' The Principles of Pale- 

 ontologic Correlation ' by Professor James 

 Perein Smith, paleontologic correlation was 

 described as being of two kinds: (1) Di- 

 rect, where the faunal regions were closely 

 connected and intermigration of species was 

 easy. An example of this is the correlation 

 of the Cretaceous of the Atlantic and Gulf 

 regions with that of Europe ; (2) Indirect, 

 where the faunal regions were separated by 

 land barriers. An example of this is the 

 correlation of the Cretaceous of the west 

 coast with that of the interior and Atlantic 

 regions. These were separated by impass- 

 able barriers, but the Atlantic Cretaceous 

 was connected with the European, the Eu- 

 ropean with the Indian, and the Indian 

 closely related to that of the west coast. 



Oppel attempted to divide stratigraphic 

 formations into faunal ' zones,' of which he 

 made 30 in the Jura alone, most of whict 

 cannot be recognized in outside regions. 

 Buckman divided the Jura into hemerce, of 

 which he found 26 in the Lias alone. 

 These, too, can not be recognized away from 

 the province where they were founded. 

 But, occasionally, the fauna of a certain 

 horizon can be identified in very remote 

 regions, this extension corresponding to pe- 

 riods of unrest, of oscillations of the land 

 and opening up of connections between re- 

 gions that before were separated. The wri- 

 ter proposes to confine the term zone to 

 such widely distributed faunas, which thus 

 become important criteria in interregional 

 correlation. Such zones are that of Manti- 

 eoceras intermerceras in the upper Devonian, 

 of Agamides rotatorius in the Kinderhook, 



