~ 
750 PROF. J. W. JUDD ON THE NATURE AND RELATIONS OF 
[The strata next in order are as follows :— 
12. Red and. variesated magls....:../...A220220 9-1 eee 
135. Bed sandstones 01.2. 54-55 men SE een eee eee soe 
14. Red and variegated marls 
15. Beds of red and white sandstone, sometimes finely laminated 
and sometimes exhibiting but little evidence of bedding. 
These rocks, which were extremely hard, were found to be 
trayersed by very numerous and closely set nearly vertical 
joints, which rendered the work of boring through them with 
the diamond crown very difficult ......0.............sceecceeececes 19 0 
16. Grey sandstone, very hard  ....:........2222520-s0seceece=5- soe 5 
17. Hard red sandstone. .....2...2.:-22:2.--<0- jib denen qeeee eae 2 0 
18. Softer red and white sandstone, finely laminated in places ...... 30 0] 
fé. 
11. Red sandstone... 4..25... 20252 Se eee 13 
S 
2 
2 
ch oor 
Bee eee wwe mee este ete were esses etter ns ee eestseeee 
The whole of the superincumbent Tertiary, Cretaceous, and 
Jurassic strata appear to be nearly horizontal in their position at 
Richmond, and it became a matter of much interest to determine if 
the underlying red sandstones and marls were conformable with 
them. Some specimens of cores showing a remarkably high dip 
appear at first sight to negative any such supposition. But a careful 
study of these apparent dips shows that they vary greatly in amount 
at different depths, and that therefore they are examples, not of 
true dip, but of oblique lamination or false-bedding. Some of the 
cores, indeed, exhibit clear evidence of false-bedding. 
[The dips actually measured in these cores of red and variegated 
sandstones and marls were as follows :— 
Dip. 
At a depth of 1255 feet from the surface............ B10 
es 1280 ie CAI eee vee 26° 
From 1288 to 1291 a3 aaah Ripe exe kur 343° 
AG ASG: DY Cte ae eens, One 32° 
At 1319 = apf] 0570 CHS Rs 35° 
At 1340 a sais) geedesas bssae 30° 
At 1348 fs EN WP SG a 30°; obscure. 
At 1352 “4 sn eee ee 27° 
At 1356 os * wsctzenas set, ene 
At 1364 Fs LS fi, ae ee 30°; somewhat doubtful. 
From 1365 to 13673 __,, youl OT eee 45°; very well marked. 
At 1372 e eis th ek oe Rose 40° 
At 13875 e eS ey eens” 40° ; nearly. 
From 1395 to 140423 _—,, Bi See 38° 
At 1408 HM SA RG Dineen 32° 
It is worthy of remark that the most discordant dips are found in 
the finely laminated sandstones, in which false-bedding would be 
best exhibited. The cores, on the other hand, in which such marked 
lamination is not to be detected, give generally dips of about 30°. 
From these facts we may infer, with some probability, that the 
strata in question have a true dip of about 30°, which is often com- 
plicated and obscured by the oblique lamination. Of the direction 
of the dip no evidence could be obtained. | 
It is hardly necessary to remark that these red sandstones and 
variegated marls have yielded no fossils. There are very marked 
differences in their characters between these beds and those met 
with in the Kentish Town boring, especially in the absence of 
quartzites and other peculiar rocks. 
