these had been a flow of volcanic raatter over a lar^e area 
of country, resting upon lower cretaceous rocks and forming 
a table land. That subsequently a large mass of less fluid 
matter had been forced up from beneath this, ratining much 
of the sedimentary strata between it and the lava of the table 
and arching, both the sediment and the tMn (comparatively) bed 
of trachyte. See sections. That the subsequent erosion had 
, 3 ^ 
carried away much of the soft beds - /The mould , and left trachyte - 
fee cas t standing almost alone. The general elevation has been 
very slight and apparently carried but a few miles in any direction. 
Day before yesterday I observed that a low antechinal extended 
for a few miles to the Westward, that the highest remnant of 
thu.s is a large flat butte. (Station). I now notice that the 
northern slope of this fold is not regular - but that another 
wave occurs in the floor of the plain between the axis and the 
line of bluffs - capped with Wo. 1 and lying South of the San 
Juan, so: 
running parallel with the first. On the back of this remain, 
the fragments of the maroon beds farming the four buttes pre¬ 
viously mentioned. I have already remarked the strange weather¬ 
ing of those beds| the regular lamination of hard and soft beds 
