84 REPORT—1858. 
ena Department. Locality. Direction of Horizontal Component. 
1. (Seine .......cscc0.0. \City of Paris...... N.E. to S.W.; three shocks. 
ISEYRES) iehcescere |W. to E.; three shocks. 
Chevreuse ......+ N.E. to 8. W, 
Longjumeau, m.,.|Direction not given. 
2. |Seine et Oise ...... Rambouillet ...... W. to E. 
GTigNON....s0..008 N.E. to S.W. 
OFSAY 2: ccccoreseees S. to N.; seven shocks. 
Meulan .......0000- N. to 8.; three shocks. 
3. |Loiret ......... seosee|NOZENE .....2ecceee N. to S. 
4, |Loire et Cher ...,../Quincay .........06 W. to E. 
5. |Indre et Loire...... |Caumacre N. to S. 
Gr HINGLE cs ssecsnecexs nce |LiaD Ge. ssceceressces S. to N. 
Le Blane, n ...... More than one shock ; direction not given. 
Met WOES sasdusseredses ease] Burges jics.csreres Vertical (soulévement) ; two shocks. 
8. |Eure et Loire ...... |\Chartres, 2......00 One shock; direction not given. 
9. |Seine et Marne ...|Donnemaire ...... S. to N.; three shocks. 
Ges (RULE, cc. seeacqeeee No record of the shock having been felt in 
11. |Oise..... Ce Cee ErSCy [el hei amp ere Sopp akan either of these departments. 
12. |Codte-d’Or...... +es.++| Bligny-sur-Ouche.|Three shocks; direction not given; very severe. 
Here, then, we have two very limited but separated earthquake districts—one 
around Paris, the other more widely spread around Tours—and a third to 
the S.W., stretching into Cote d’Or, in which we have the observed or hori- 
zontal direction of shocks from N. to S., from S. to N., from W. to E., and 
from N.E. to S.W., and in one place said to be vertical. In the Paris dis- 
trict the extreme distance apart of the places of observation does not exceed 
30 English miles, the average being under 15 English miles. 
In the Tours district the extremes are under 70 English miles apart, and 
the average distance under 30 miles. The central part of one region is not 
more than 150 miles from that of the other; and neither district is more 
than about 70 miles distant from the axial line of the chain of hills that 
separates them, and in the prolongation of which to the S.W. the third 
district is widely spread, taking the general line of axial direction. 
Making every abatement that imperfect observation can justify, there 
remains abundant proof, in this example, that even in places within view of 
each other as to distance, but situated over heterogeneous formations, and in 
a country of broken and irregular surface, the superficial direction of shock 
may present anomalies at first sight apparently admitting of no analysis, and 
in any case incapable of giving any direct information as to prevailing direc- 
tion, or position of focus, by mere seismometric observations. 
The third and last example we shall take from India, as one not devoid of 
a larger interest also. In the map (Plate XIV.) a very rude outline is 
given of the geological formations of India, in a merely seismic relation 
however, z.e. with reference to relative hardness, density, and elasticity of 
the rocky masses,—thus distinguishing them only into the six great divi- 
sions of crystalline or granitoid, old stratiform, secondary (from carboni- 
ferous to cretaceous), tertiaries, alluvial plains, and some igneous porphyries, 
diorites, &c. In the colouring of this I have to acknowledge the kind as- 
sistance afforded me by Professor Phillips. This map has been fully de- 
scribed in “ Second Report on the Facts, &c.” (Brit. Assoc. Trans. for 1851, 
p- 313 et seq.), where it should have appeared originally, but was, at a late 
moment, prevented by an accident connected with its completion. I shall — 
therefore, referring the reader to the former report, merely notice here the 
facts as relating to seismometry. 
