470 SAMUEL WEIDMAN 



1. The heterogeneous character of the deposits is shown by a 

 wide range in source, size and shape of the constituents of the con- 

 glomerate. Limestone is the most abundant boulder constituent 

 in the Arbuckle area, as limestone is the most common rock of the 

 Arbuckle region. In general, limestone pebbles from all the 

 Arbuckle Mountain formations older than the particular conglom- 

 erates are brought together in each of the local deposits. In 

 places there may be a predominance of boulders from adjacent or 

 underlying formations, but very generally there is a complete mix- 

 ture in varying proportions of rock debris derived from a wide range 

 of formations. While there is a general tendency for coarse and 

 fine beds of conglomerate to succeed one another, the individual beds 

 show very Kttle or no assortment. In the same bed the constituents 

 will usually range from small pebbles up to boulders from i to 3 feet 

 in diameter. 



The shape of the pebbles and boulders also varies greatly, rang- 

 ing from rounded to sub-angular and angular. In some deposits 

 angular constituents predominate, in others rounded boulders are 

 most abundant. Usually the more rounded and polished the boul- 

 ders the greater the distance they have been transported. In some 

 of the beds, at least, the most angular blocks have been derived from 

 adjacent formations. However, any generalization meets with 

 many exceptions, and well-roimded and very angular material from 

 the various formations are often found together. 



2. The non-residuary character of the pebbles and boulders is 

 one of the most striking characteristics of the conglomerate. The 

 constituents do not represent the end products of weathering, such 

 as generally characterize basal conglomerates formed under ordinary 

 sub-aerial or sub-aqueous conditions. On the other hand, the con- 

 stituents are easily decomposable carbonate and silicate rocks 

 which, judging from their angular shape and fresh, unweathered 

 character, have been removed rather rapidly from their original 

 source and transported considerable distances without much chemi- 

 cal decomposition. 



It is well known that conglomerates or breccias formed of non- 

 residuary material are characteristic of deposits on mountain slopes 

 accumulated under desert conditions. The character of these 



