Davis.] 
328 
[Nov. 18, 
ilton slopes could be seen, they possessed no distinct bench lines ; 
- and I infer that any remnants of the old delta on that side of the 
valley are small and inconspicuous. 
The road soon descends from the remnant bench just men- 
tioned and for half a mile skirts the broad flood-plain of the 
Catskill ; a beautifully smooth expanse of well cultivated fields at 
a height of about 180 feet. It then rises abruptly to a level of 
270 feet, where the surface is again stony and pebbly, but the 
stones are seldom over six inches in diameter. This flat is cut 
on the south into successive benches, forming a broad stretch of 
terraces towards South Cairo ; but the surface of the upper flat 
itself seems to descend eastward and northeastward towards the 
valley wall ; this needs further study, but from our brief view of 
it, I am inclined to regard it as standing near the front of the 
i main delta of the Catskill. At any rate, there is no other well 
marked remnant at so great a height as this until reaching the 
mouth of the Potuck valley, a stream of moderate size coming 
from the north where its head lies in Albany county, above east 
Greenville, about fifteen miles away. Here a flat field of small 
water- worn pebbles lies at a height of 280 feet ; its extension up 
the Potuck valley may be seen for a third of a mile before it is 
hid in trees ; but its front in the Catskill valley is of more im- 
portance, for it possesses well-marked, divergent lobes, distinctly 
of original constructional form, not the product of subsequent 
erosive action. The lobes are not so smoothly formed as is often 
• the case with the frontal lobes of the glacial sand plains that I 
have studied in New England, but they are of definite form 
enough to convince one that they are not the product of 
wasting since they were made. The hollows between the 
lobes lead up to the level of the pebble plain, receiving no back 
country drainage, and hence not gathering enough water to cut 
the hollows out. The sketch map shows that in the first remnant 
3 of the delta below the great Cairo cobble-field, a small stream 
comes down from the Hamilton hills on the north and cuts a 
trench across the terraced sands and gravels ; but elsewhere the 
margins of the terrace benches are smoothly curved, as they were 
left by the meandering Catskill ; hence we may be sure that the 
general wasting of the surface has not been sufficient to form 
« interlobate hollows not occupied by streams, such as occur on 
the front of the Potuck delta. They must be of constructional 
