ABT. 5. CRICOIDS FROM THE UPPER CRETACEOUS SPRINGER. 3 



frequently reduced to 5. The sectors are rather deeply impressed 

 when freely exposed, but in the specimens as here preserved are 

 usually obscured by matrix. 



Occurrence and hor'izo7is. — Upper part of San Felipe formation 

 and lower and upper parts of the Mendez formation of the Upper 

 Cretaceous, at several localities on Chocoy and Las Flores ranches, 

 65 to 85 kilometers northwest of Tampico, in the State of Tamaulipas, 

 Mexico, as enumerated below : 



Upper part of San Felipe formation — Las Flores hacienda in an 

 arroyo about 6 kilometers west by south of Manuel station (M. G. O. 

 Acq. Nos. 138 and 268) ; and in an arroyo about 3^ kilometers west 

 by north of Manuel station (M. G. O. Acq. No. 135) ; Chocoy haci- 

 enda, in an arroyo about 3 kilometers west-northwest of Chocoy sta- 

 tion (M. G. O. Acq. No. 142) ; and in an arroyo four-fifths of a kilo- 

 meter north of old Chocoy hacienda house (M. G. O. Acq. No. 143) , 

 and loose in material thrown from an excavation for a tank four- 

 fifths of a kilometer south of old Chocoy hacienda house (M. G. O. 

 Acq. No. 270). 



Lower part of Mendez formation — On Chocoy hacienda, in a ^ully 

 just west of the track of the National Railways of Mexico, 1^ kilo- 

 meters northwest of Chocoy station (M. G. O. Acq. 141), and in a 

 ditch along the Tampico road, half a kilometer south of the old 

 Chocoy hacienda house (M. G. O. Acq. No. 271). 



Upper part of Mendez shale — On Chocoy hacienda, in g:idlies at 

 Los Borregas, 4 kilometers east by south of Chocoy station (M. G. O. 

 Acq. No. 272). 



The stem fragments are found through a vertical range of 200 or 

 250 meters. The type (pi. 1, fig. 1) was found in the upper 

 part of the San Felipe formation, 6 kilometers west bj^ south 

 of Manuel station. Modifications of species doubtless occurred dur- 

 ing the time interval represented by so great a deposit, but these 

 can not be determined from the present material. A species was 

 described by de Loriol from the Upper Cretaceous of Africa in 

 Tunis ^ as Balanocrinus africanus^ which was evidently a less robust 

 form, having small cirri and more delicate crenelations on the joint 

 faces. 



Along with the stem fragments in the upper part of the Mendez 

 formation are some remains of an echinoid with numerous very small 

 spines, not sufficiently perfect for determination of the genus, but 

 evidently of similar type to some forms which have been found in 

 the Upper Cretaceous of Texas and Alabama. 



2 In Peron, Exploration scientitique de la Tunis, 1893. Paleontologie,, pi. 31, figs. 

 S9-53. 



20107— 22— Proc. N. M, vol. 61 4 



