244 



C. L. HERRICK 



Leucompton beds and extends upward, Strehlopteria begins in the 

 Earlton. So far as can be determined at this writing, the position 

 is near the horizon indicated by lola hmestone, or within the 

 Pottawatomie formation of Haworth. This is above the base of 

 the Upper Coal Measures. 



Below are given in tabulated 

 form, for comparison, some of the 

 more complete sections across the 

 Permo- Carboniferous. It will be 

 found that there is always a well- 

 marked change in lithological 

 character of the rock at the horizon 

 of the Manzano quartzite. Here is 

 evidence of an unconformity by 

 overlap. The lime breccias or small 

 strata of lime with angular frag- 

 ments of earlier lime and granite are 

 quite characteristic of this general 

 belt, and the Manzano beds them- 

 selves usually contain vast quanti- 

 ties of red granitic debris. Often 

 vein quartz is 

 present, and it is also common to find im- 

 pressions of tree trunks. All of these phe- 

 nomena indicate proximity of land and a period 

 of disturbance. The Sandia formation is 

 easily distinguished, but it is more difficult to 

 decide upon divisions of the Upper Coal 

 Measures above that section. In general, there 

 is a change of fauna, though numerous 

 species pass unchanged throughout. Productus 

 punctatus, Dielasma bovidens, and Meekelia are Fig. 4. — Lepidoden- 

 characteristic of the upper portions. The large ^''^^ thwaitesi, sp. n. 



. . ... 1 (Single bolster, en- 



Fusulina is found at a higher level than the ^ g^j \ 

 common F. cylindrica. 



Fig. 3. — Lepidodciidron thwaitesi, 

 sp, n. (One-half natural size.) 



