1836.] 



Laterite, or Iron Clay, 



113 



of it slaty (No. 14), are found imbedded in the less compact kind of 

 laterite, and in the gravel. This ore, I think, contributes to form the 

 more compact laterite, also, but it appears to have been more broken 

 and subdivided, and is therefore not so easily traceable. 



The laterite varies very much in appearance. Sometimes it is very 

 hard, compact and heavy, highly ferruginous, of a deep red colour, 

 penetrated in all directions by the sinuosities containing the red and 

 yellow and white earths. In this kind the red sandstone nodules are 

 very distinguishable (No. 15). Some masses are nearly half compos- 

 ed of the white lithomargic earth, which renders it very crumbling 

 (No. 16). 



Other varieties exhibit a pisiform structure, numerous rounded peb- 

 bles being united together by a yellow clayey cement ; this seems of 

 recent origin (No. 17). 



Again, in many superficial situations, it is a mere gravel, possessing 

 very lil tie coherence, and, apparently, formed from the debris of the 

 laterite itself. The pebbles, composing this gravel, still exhibit the 

 structure of the red conglomerate sand-stone, and of the ochrey iron ore 

 (Nos. 18 and 19). 



Innumerable pebbles strew the face of the ground, in all directions, 

 a great number of which, on fracture, display the structure of the nodu- 

 lar imbedded sand-stone (No. 20). I should observe, that I no where 

 saw this sand-stone in any other form than that of fragments imbedded 

 in the laterite, or detached thence, and undergoing another rolling 

 process on the present surface of the ground. 



Equally numerous are the scattered fragments of ochrey iron ore, 

 described above. I no where found this substance as a vein, or in mass. 

 It would seem probable that it existed in the original crystallized 

 rocks ; and that, under the watery disrupting influences, to which the 

 whole ingredients of the formation have evidently been subjected, this 

 ore was very much comminuted, and the more minute particles 

 contributed the greater portion of the ferruginous paste, so charac- 

 teristic of all the rocks around. 



To the eastward of the lake, in the low grounds, masses of the 

 laterite jut forth from the soil ; and no other description of rock is to 

 be seen in any direction. 



On Colonel Cullen's property, on the east side of the lake, a trench 

 has recently been cut, ten or twelve feet deep, and thirty or forty feet 

 long. The first five or six feet from the surface consist of a red clay, 

 containing a few fragments of the red conglomerate sand-stone, some 

 nearly a foot in diameter, and, here and there, a piece of the ochrey 

 iron ore. The sub-stratum is a yellowish, tenacious clay, with no 

 imbedded pebbles. An even line of demarcation distinctly divides 

 these two deposits, which do not at all blend into each other. 



