308 R. T. HILL GEOLOGY OF RED RIVER. 



previously described in southwest Arkansas extend into Texas. South 

 of Paris, as in Arkansas, this division consists of three conspicuous 

 members. The base is a pure white chalk rock, the White Chffs chalk 

 of my Arkansas section, but called the Anona chalk in Texas, accom- 

 panied by beds of glauconitic chalk or chalky glauconite, which in the 

 field we have designated cement rock.^ Above this are glauconitic marlsj 

 called Brownstown marls in Arkansas and Kickapoo marls in Texas, 

 which bear a growth of hardwood,t including Bois d'Arc. Finally 

 come the Glauconitic sands, with the fauna of the greensand marls of 

 New Jersey, but generally more arenaceous. It is not known what has 

 become of the Austin chalk in this section, but my hypothesis, backed 

 by some evidence, is that to the southward it has been faulted down. 

 The Anona (White Cliffs) chalk is an entirely distinct and higher bed, 

 for it is underlain by the Taylor (Exogyra ponderosa') marls which overlie 

 the Austin chalk, and on our next profile we will see that the Austin 

 chalk reappears in its normal position to the^eastward in Arkansas. The 

 Anona chalk is stratigraphically the same as the White Cliffs chalk X of 

 my Arkansas section, and is analogous in position to the upper white 

 chalk of England, while the lower Austin chalk is analogous to that 

 of the lower chalk of that country. In chemical analysis they also 

 resemble, the upper having about 98 per cent, of lime, the lower aver- 

 aging about 89. This lithologic coincidence is worthy of ncTte.' 



ULTIMA THULE SECTION. 



This runs south from the Ouachita mountain along the Choctaw^- 

 Arkansas boundary. 



The Trinity still rests on the upturned Paleozoic, but the Cretaceous 

 formation ceases to predominate, and the estuarine and Pleistocene 

 fluviatile deposits now constitute the chief surface features. The Good- 

 land limestone ceases to form the prairie divides and descends into the 

 lowest flood plain of Little river, covered by later deposits, and does not 

 appear again to the eastward. The Washita beds form the higher bluffs 

 of the south bank of the stream, and likewise dip beneath its level a few 

 miles east of the profile. The Dakota also disappears still eastward, at 

 Morris ferry. 



The divides along this profile are flat plains — veritable mesas — capped 

 by one of the greatest deposits of stratified gravel and bowlders in our 

 country, the probable continuation of the late Neocene deposit so ably 



*This consists of a chalky matrix specked with minute grains of glaaconite. 



fThis is the only marly terrane in the entire range of Cretaceous formations in Texas which is 

 covered by arborescent vegetation. 



Jin November, 1892, the writer found a single specimen resembling Annnchytes ovata in this 

 chalk at White Clitfs. It was impossible for Professor W. B. Chirk to insert it in his publication 

 on Mesozoic Echinodermata, as it had gone to press. 



