28 REPORT— 1868. 
the “fault.” It is not a little remarkable that while a range of cliffs 
somewhat of the same nature as ITV A* W.N.W.-E.S.E., No. 1, extends 
from IV Af towards Horrow, the craters [VY Af and LV Af with Hor- 
vox forming its §.E. portion, the crater IV A**, and the cliffs IV A? 4, 
TV Af 10, TV Af 43, and IV A & “ lie in the prolongation of [LV A* W.N.W.- 
E.S.E., No. 1. Does this point to a focus of wpburst in the neighbourhood 
of Horrox, contemporaneous with the fault IVA’"! IV Af 20 TV A*?, and 
marked by the three large openings, Horrow, IV AP 4, and IV Af 19? If 
so, the line of cliffs extending from IV A**! to TV A? 18 would probably 
be more ancient than the “fault,” the upburst occurring 8. of the line of 
cliffs. It is to be remarked that on the line of cliffs a few small craters 
only are found, of which IV A*? and IV Af? are the principal, scarcely 
exceeding 8” in diameter, and at a considerable distance from each other. 
In describing the fault (see letterpress, areas IV A*, IV AS, p. 20, and Re- 
port. Brit. Assoc. 1866, p. 256), we suggested that it might be more recent 
than the “ray from Tycho,” on which the steep and rugged W. border of 
Albategnius occurs. On the parallel ray to the E. we noticed two points of 
upburst, one near IV A¢**, the other near IV A¢*? (see letterpress, areas 
IV A*, IV AS, p. 39, and Report Brit. Assoc. 1866, p. 275), the activity of 
which might be more ancient than that of [LV A”?. Should these considera- 
tions at all approximate to the truth, then we have a probable recent epoch 
for the production of the group of craters near the W. portion of Hipparchus. 
The close similarity, both in form and direction, of the valleys IV A**? and 
TV A"18 on opposite sides of Hipparchus also points to the priority of age of 
the line of cliffs in which IV A“*? occurs, as compared with the floor of Hip- 
parchus, which appears to be more recent. 
31(x). The 8.8.W. part of the valley IV A* 7, 
This valley is interrupted but not obliterated by the fault [IV A” 1! TV A8 20 
IV A*7?. At first, in the neighbourhood of IV A*%8, it is wide; but as the 
fault is approached it becomes much narrower. The W. side of the crateri- 
form depression IV A?! appears to be part of the W. slope of this valley, on 
which the E. rim of the crater [V Af 4 has protruded, which indicates a more 
recent epoch for the production of IV Af 14, Beyond the group connecting 
TV Af l4 with IV A 16, the valley IV A*77_ LV A8& 2! can be traced as a narrow 
dark cleft through the ascent to the bright spot [V A® ®7._ This cleft is not in 
Schmidt’s catalogue. 
32. A craterlet 8. of TV AF, E. of [LV Af, 2”-70, mag. 0-16. The fifteenth 
in order on area LY AB, 
33. The W. part of the 8. portion (IV A* 4°) of the second wall of Rheticus 
(see letterpress to areas IV A*, LV AS, p. 12, and Report Brit. Assoc. 1866, 
p. 248). It has been dislocated by the fault TV A”! TV A820 TY At ?, 
34, A pit S.S.E. of IV Af} adjoining IV Af 8, 
This pit is surrounded by a broad hilly border ; longest diameter of border 
=7"-18, shortest=4'-94. It, with the E. border of IV Aé 5, is situated 
very exactly in the line of ‘fault IVA") LY AP 20 War m, TY Af 45; 
TY A 34, and TV A’ 28 form a connexion between IV Af 4 and IV AB 16, 
35(x). A mountain W.N.W. of IV Af 19, on the line of fault IV At 
IV A® ®, also on the “ ray from Tycho ” on which Besselis situated. The two 
intersect at this mountain, which appears to have been thrust forward in 
the line of cleft” IV A#%, 
36, The mountain-peak at the W. angle of IV A? 18, 
37. The bright white spot (crater) on ae W. slope of TV Af 38, the twelfth 
crater in order on IV A8, 
