716 



SCIENCE. 



[N. S. Vol. XV. No. 383. 



5. The catalytic action of platinum black is 

 diminished through the addition of small 

 quantities of those poisons which, according to 

 Kastle and Lowenhart, interfere with the 

 catalytic action of lipase, e. cj., potassium 

 cyanide, hydrogen cyanide, phenol, mercuric 

 chloride, salicylic acid, silver nitrate, chloro- 

 form, sodium fluoride and others. 



In all the experiments bacteriological pre- 

 cautions were used to exclude the possible in- 

 fluence of bacteria in these results. Control 

 experiments showed that the above hydrolytic 

 and synthetic action did not occiir in the ab- 

 sence of platinum black. 



My sincere thanks are due Professor Loeb 

 for his helpful and valuable suggestions in 

 these experiments. 



A full report of these experiments will ap- 

 pear in the American Journal of Physiology. 

 Hugh Neilson. 



Hull Physiological Laboratory, 

 University of Chicago, 

 April 12, 1902. 



THE JACKSON OUTCROPS ON RED RIVER. 



The Jackson stage of the marine Tertiary 

 appears on the Red River in Louisiana at three 

 points, known to the writer from recent in- 

 spection. The northernmost outcrop is the 

 well-known long low blufi at Montgomery, 

 which is probably the most extensive and pro- 

 lific exposure of the stage now existing. The 

 fossils are contained in profusion in a light 

 blue-gray argillaceous marl, the bed being some 

 six feet in thickness and having a very pro- 

 nounced even dip, through the approximately 

 quarter mile of exposure, of about one foot 

 in fifty along the straight course of the river, 

 which is here nearly due south, until it dis- 

 appears beneath the surface at low water. 



The next exposure occurs about a mile and 

 a half below the Montgomery outcrop, on the 

 estate of Mr. T. W. Kimbrel. These beds, 

 which are also exposed along a line bearing 

 but a few degrees east of south, have so slight 

 a dip that they appear to be practically hori- 

 zontal to the eye and are composed for the 

 greater part of greenish-black and brick-red 

 clays. This deposit is not so rich in species 

 as the Montgomery bed and is much more 



limited in horizontal extent; it bears nearly 

 due south from the Montgomery bed. 



The third exposure occurs at the eastern 

 base of the high and very picturesque bluff, 

 more than a mile in length, about three miles 

 below the Kimbrel beds and limiting the es- 

 tate of Mr. John Young, and is in like man- 

 ner composed of blackish and red clays; it 

 bears about thirty degrees south of east from 

 the Kimbrel deposits and may be known as 

 the Young's Bluff bed. Both the Kimbrel and 

 Young's Bluff beds are characterized by a 

 profusion of a large Pinna and of Venericardia 

 planicosta, Volutilithes and Pseudoliva. 



The Kimbrel bed belongs to a horizon no- 

 ticeably distinct from the Montgomery out- 

 crop and contains immense numbers of an 

 extremely minute Lucina, which is without 

 doubt one of the smallest known bivalves. It 

 is suborbicular, generally a little higher than 

 long, slightly inequilateral, with the posterior 

 side more broadly rounded than the anterior, 

 strongly inflated, thick and heavy in sub- 

 stance, with the hinge thick and strong, all 

 the cardinal teeth large, and the lateral teeth 

 also very thick and almost equidistant from 

 the cardinal. The beaks are small and mod- 

 erately elevated, the lunule long, narrow and 

 rather ill-defined. The ventral edge is crenu- 

 late within and the exterior surface marked 

 with feeble close-set lines of growth and gen- 

 erally also three or four deep concentric 

 grooves of arrested growth. The length of the 

 largest valve in an extended series is 1.35 

 mm., the height 1.4 mm. It may be called 

 Lucina atoma, and is brought forward with a 

 name at the present time because of its impor- 

 tance in being the characteristic fossil of the 

 Kimbrel horizon. 



It is impossible at present to state the num- 

 ber of feet of strata separating this horizon 

 from the Montgomery, for it is probable that 

 the latter stratum changes its dip shortly 

 after disappearing below low water, but there 

 are several changes in the nature of its fos- 

 sils that indicate considerable lapse of time. 

 This is shown, for example, in Venericardia 

 planicosta, in which the hinge seems to be 

 less developed and the substance of the entire 

 shell thinner, and in Volutilithes, where the 



