78 bulletin: museum of comparative zoology. 



thic, should be sufficiently distinct from true clays to receive a specific 

 name in the system of classification; but none occurs for modern 

 deposits of this type in accepted usage. Such lithified glacial rock- 

 flours may be called pelodite from tttjXcoStjs, es (tttjXoj, eldos), ite, clay- 

 like rock, in reference to the fact that these rocks often clay-like or 

 shaly in texture and structure, when first formed may differ widely 

 from typical clay in the very small amount of kaolin which they 

 contain. Pelodite is to be differentiated from pelite also by its in- 

 cluded glacial pebbles. 



Closely associated with modern glacial deposits though distinct in 

 origin and often very differently distributed is the fine mainly eolian 

 deposit known as loess frequently- derived from glacial moraines 

 through their deflation by winds. Some of the finer sediments of the 

 Brazilian Permian resembling clays seem to be of this origin. Such 

 lithified deposits of loess may in analogy with tillite be called loessite, 



AYith these preliminary statements it is to be presumed that the 

 following tabulated classification of glacial deposits will need no 

 further explanation. 



Modern unconsolidated Divisions depending Ancient lithified 



deposits. on form. deposits. 



Till Tillite. 



Boulder-clay do. 



Moraine, frontal, ground-, 

 drumlins 



Glacial gravels Glacial conglomerates. 



Eskers, kames; 

 glacial deltas. 

 Glacial sands Deltas and plains Sandstones. 



Glacial clays Pelodite. 



Loess Loessite. 



Classification of the Glacial De-posits of South Brazil. — With the 

 above simple classification in mind, it appears that the Permian 

 moraines of south Brazil presents several facies of a glacial series, 

 both stratified and unstratified. 



In the tillite group must be placed the typical blue boulder-clays 

 of the Rio Jaguaricatu section, the gravelly beds wdth large angular 

 blocks, beds presumably of the ground-moraine or subglacial type. 

 Unfortunately the limited exposures in the deeply forested river 

 valley do not permit of a determination of the topography of these 

 ancient beds of drift. In somewhat sharp contrast with the analogue 



