DABTON.] 
MARYLAND. 
137 
and Belair roads, and the high region about Catonsville. In these 
outlying extensions the basal gravels constitute a capping on the 
crystalline rocks which averages from 10 to 30 feet in thickness. The 
superficial distribution of the crystalline rocks and the contour of the 
floor on which the Potomac formation lies are represented in PI. VII. 
The principal structural relations are shown in the sections on PI. VIII. 
On Patapsco Eiver Neck the Potomac formation rapidly thickens as the 
crystalline rock floor descends to the eastward, and at Sparrow Point 
the thickness was found to be 500 feet. The higher ridge which extends 
along the northern portion of this neck is capped by a thin mantle of 
earlier Columbia gravels and loams, and the lower terraces consist of 
later Columbia loams and sands, with some gravel in the lower beds. 
These formations, however, are not involved in the question of the 
deeper water supply. 
The crystalline rocks present considerable variety of materials, but 
gneiss and granite, or "gray stone," and the "nigger head," or gabbro, 
are the most conspicuous varieties. They are all considerably fissured 
and often deeply decomposed along fissures or veins of moderate width 
and extent. The fissures or veins are usually nearly vertical aud 
extend from northeast to southwest. They are water-bearers in greater 
or less measure, but their distribution and extent have not been deter- 
mined, except in the case of the one along Belair road, which has been 
tested for a short distance. 
List of deep wells in Baltimore. 
Locality. 
Depth. 
Diameter. 
Capacity 
per 
minute. 
Height 
to which 
water 
rises, a 
Eemarks. 
Canton. 
Feet. 
Inches. 
Gallons. 
Feet. 
1. MarylandFertilizerCo., Clinton 
140 
2£ and 1* 
15 
- 8 
and Eleventh streets, 3 wells. 
2. Stickney Iron Co., Clinton and 
Eleventh streets. 
3. Lazaretto Fertilizer Co., Clin- 
f 130 
I 175 
I 226 
220 
u 
30 
— 2? 
— 3 
6 
Many. 
—22 
Water also at 155 feet. 
ton and Tenth streets. 
. 220 
3 
4. Baltimore Guano Co., Clinton 
and Ninth streets. 
170 
j 125 
3 
12 
1 Many. 
[ 80 
3 
J 
5. Susquehanna Fertilizer Co., 
±200 
10 
Many. 
—20 
Water also at 120 feet. 
First street and Seventh ave- 
nue. 
6. Griffith & Boyd, Clinton and 
Fifth streets. 
. 90 
I 190 
12 
Many. 
Many. 
10 
7. Orient Distilling Co., First 
street and Third avenue, 2 
wells. 
210 
185 
} 65-80 
Orient Distilling Co., First 
) 
street and Third avenue, 3 
I 125 
Poor water. 
wells. 
I 
a— ,fe 
et below si 
lrface. 
