102 SPOLIA ZEYLANICA. 
belongs to that series of rabbly débris which the Public Works 
Department describes under the sometimes misleading name 
of gravel ; while the upper stratum consists of a red earth free 
of stony content. The whole series varies in thickness up to 
50 feet or more. 
The larger of the “gravel” fragments may consist of 
quartz in various stages of angularity and roundness, or of 
irregular concretionary bodies consisting chiefly of ferric oxide 
and angular sand. Every gradation exists between a good, 
well-rounded gravel, and a deposit in which the concretionary 
bodies are paramount.* 
The quartz pebbles are seldom more than a few inches in 
length, while the longest axes of the concretionary bodies 
hardly ever exceed aninch. The matrix of the beds is a finely 
divided red material, which varies considerably in proportion 
to the mass, even within very limited areas. Pebbles of 
crystal quartz, when present, are generally corroded over their 
entire surfaces ; with milky quartz it is otherwise. 
Boulders, sometimes weighing over a ton, occur locally. 
All the pebbles are remarkably free from iron staining or 
any colouring matter, which cannot be removed with a 
scrubbing brush and a little water. 
The gravel bed, as for the purposes of this paper I will call 
the lower of the plateau deposits, overlaps all the older rocks. 
It is to be seen sometimes resting on the archzean, sometimes 
on the older sedimentaries of the North-Western Province,t 
and sometimes on the various members of the Kudremalai 
(Kuthiraimalai) series. It fills up the irregularities of the 
ancient surface below it. Nowhere does it overlie the alluvials 
of the rice fields, the coastal (or “ reef ’’) sandstone,§ or any 

* Similar concretionary bodies are to be found in the beds of practi- 
cally all streams which run dry in the rainless seasons. 
+ The Tabbowa beds. These have never been described, except in an 
official (unpublished) report on the district by the present writer. 
{ Though it has been necessary to make several references to these 
rocks in my official reports, no detailed description of them has yet been 
produced. It will suffice for the present to say that they are younger 
than the Tabbowa beds (older sedimentaries of the North-Western 
Province), and older than the high gravels which terrace the main river 
valleys. 
§ For some account of this, see ‘‘ Equus zeylanicus’”’ (‘‘ Spoha 
Zeylanica,”” Vol. X., Part 38, 1916, p. 267). 
