70 H. E. Gregory — A Geologic Reconnaissance 



Feet. 



28. Sandstone, gray, coarse, with very thin hands of red 



calcareous shaly sandstone. Few pebbles except of 

 brown shale 14 



29. Limestone layer in chocolate shale ; upper surface 



sun-baked and marked by mud cracks, worm tracks 



and footprints (?) 0.5 



30. Sandstone, brown, thin-bedded, cross-bedded 5 



31. Limestone, thin-bedded, shaly, arenaceous; surface of 



separate layers strewn with fine micaceous sand; 

 sun-dried, sun-cracked; shows footprints (?) 1 



32. Sandstone, gray, with thin beds of shale and shaly 



limestone 14 



33. Shale, chocolate, sandy, with mud cracks, baked sur- 



faces, tracks, etc. Strike K 70°-80° E.; dip 30° S. 

 Open joints, producing waterfall, trend 1ST. 20° W. 

 and E. ; both sets nearly vertical 6 



34. Sandstone, gray, with interbedded brown and chocolate 



calcareous shaly sandstone and thin limestone .... 30 



35. Concealed by gravel 180 



36. Sandstone, brown, and chocolate shale in alternating 



beds ; dip nearly horizontal 45 



1208.5 



On the divide between the headwaters of the Chchocco and 

 Llavlliccasa, branches of the Huancaro, where the ]\Iolle-Orcco 

 conglomerate is involved in a knot of twisted folds, the follow- 

 ing* section, typical for the area southwest of the Huancaro, was 

 measured : 



VII. Section of Molle-Orcco conglomerate member of the 

 Huayllabamba formation near the head of Rio Chchocco. 



Strike N 20° W; dip 80° SW. 



Feet. 



1. Sandstone, gray and brown, and conglomerate; pebbles 



irregularly distributed 20 



2. Shale, chocolate-brown, with layers of sandstone 3 



3. Sandstone, brown, calcareous cement, cross-bedded; 



lenses of clay pebbles and of conglomerate 20 



4. Shale and shaly sandstone, chocolate, calcareous 4 



5. Conglomerate and coarse sandstone, brown; subangular 



and rounded pebbles as much as 1 foot in diameter 

 of red and gray quartz, feldspar, sandstone, shale, 

 limestone, granite and diorite, and slate 16 



6. Shale, chocolate, arenaceous 6 



69 



