PRONORirivS, MEDLICOTTIA. 47 



Pronorites siekenthai.i Smitli, sp. uov. 



PI. XI, rto-8. f)-!. 



1896. I'rononU'x .sp. indct.. J. P. Smith. Pro.'. Am. Philos. Soc, Vol. XXXV, p. 



270. I'l. XX. tio-s. 2a-c. 



In the Middle Coal Measures of Scott County, Ark., T. 1 N., R. 28 W., sec. 

 4, SE. \ of SE. \, was found a single fragment that seems to belong to Prod- 

 romites. It is septate, and must have belonged to an individual aVjout 2^ 

 inches in diameter. The sides are smooth and little embracino- and almost 

 parallel; the coil is thin and discoidal, and the ventral or external portion 

 seems to be only slightly arched. From the umbilicus toward the ventral 

 portion are seen five lateral lobes that are long and pointed, the saddles 

 being somewhat rounded. The siphonal lobe and part of the first lateral 

 lobe are not seen, that ])art of the shell being worn so that they can not be 

 made out, but enough of the first lateral lobe is visible to show the second- 

 ary saddle that divides it. The septa are very close together, as seems to 

 be the case on all species of this genus. 



The nearest known relative is Pronorites cydololms Phillips, var. uralensis 

 Karpinsky." The lobes figured on PI. I, fig. 4, of Karpinsky's monograph 

 are very like those of the specimen from Scott County, and the general 

 shape of the coil, the height, and the amount of the involutidu are about 

 the same on both. 



Occurrence. — Middle Coal Measures, Scott County, Ark., T. 1 N., R. 28 



W., sec. 4. 



Genus Medlicottia Waagen. 



It was once thought that ammonites were not found below the Meso- 

 zoic, and that all the Paleozoic ammonoids were g-oniatites. A survival of 

 this idea is seen in Dr. C. A. White's description of the Permian ammonites 

 of Texas as "^lesozoic types." But to-day it is recognized that ammonites 

 are quite as characteristic of the Permian as of any later formation. 



Medlicottia was one of the first Paleozoic ammonites to be described, 

 a species of this genus having been published l)v jMurchison, Verneuil, 

 and Keyserling'' under the name Goniatites orhignyanus, from the Artinsk 

 formation, Lower Permian, of eastern Russia. 



n Ammoneen der Artinsk-Stufe, p. S, PI. I, tig. 4. 



''G^ol. Ru.ssie <r Europe et(\. Vol. II, p. 37.i, PI. XXVI, fig. 6. 



