182 Lee — Lower Paleozoic Rocks of Central New Mexico. 



age were obtained and it is possible that both Mississippian 

 and Devonian rocks may be found here, for they are known 

 to occur at Lake Valley and at Hillsboro, a few miles to the 

 west.* 



About eight miles south of Shandon near the south end of 

 the Caballos Mountains, the older Paleozoic rocks are again 

 exposed, although considerably folded and faulted. No 

 detailed section of them was made owing to their disturbed 

 condition, but the following generalized section with estimated 

 thicknesses indicates their order of succession : 



Section of Mocks exposed near Red Cabin, eight miles south of 

 /Shandon, New Mexico. 



■ Thickness 

 estimated. 

 No. Ft. 



(1) Limestone, blue (age, lower Pennsylvanian) 500 



Unconformity of erosion. 



(2) Shale, black (age, Devonian (?) ) _ _ _ _ 1-300 



(3)* Limestone, cherty (age, late Ordovician) 500 



Angidar unconformity. 



(4) Limestone, cherty (age, early Ordovician)..... 200 



(5) Quartzite (age, not determined) _. 300 



(Base not exposed.) 



A few fragmentary fossils were found in the cherty lime- 

 stone (No. 4) of the Red Cabin section. Although they are 

 very poorly preserved, Ulrich recognizes them as Ophileta cf. 

 com/planata and Llormotoma cf. artemisia (Billings species) 

 and refers them with some confidence to the lower Ordovician 

 (Beekmantown). 



Cherty limestone about 500 feet thick, that is probably 

 equivalent to the lower chert (No. 3) of the Shandon section, 

 lies unconformably upon the early Ordovician chert in some 

 places and upon the massive quartzite (No. 5) of the Red 

 Cabin section in other places. Fossils were collected from it 

 at the base, near the middle, and at the top, but as Ulrich 

 includes the three lots in one general fauna, they may be 

 combined as follows, together with his notes concerning them : 



Rafinesqxtina, n. sp. (characteristic of Western Richmond). 



Rhynchotrema capax (most characteristic Richmond fossils). 



Facosites asper (late Ordovician and Clinton). 



Retraia, sp. undet. 



Lindstromia, sp. undet. 



Dalmanella \f iSchizophoria), sp. undet. 



* Gordon, C. H. and Graton, L. C, Lower Paleozoic Formations in New 

 Mexico, this Journal, xxi, pp. 394-395, 1906. 



