346 
PALJEONTOLOGY OF NEW-YORK. 
710. 21. MURCHISONIA BOYDII. 
Pl. LXXXIII. Fig. 3. 
Loxonema boydii. Report on the 4th Geological District of New-York, 1843, p. 138 ; fig. 3, p. 137. 
Spire moderate ; volutions about six, gradually enlarging to the last one, which is somewhat 
ventricose ; umbilicus small. 
The few impressions of striae remaining upon the cast are not sufficient to decide whether the 
fossil be a Loxonema or Murchisonia ; and since all the Galt specimens, which are of the same 
age, appear to belong to Murchisonia, I have concluded to refer this one to the same genus. 
This species approaches in form to M. loganii , but is much smaller, and the volutions slightly 
more oblique. 
Position and locality. In the argillaceous limestone near the base of the Onondaga-salt 
group, Newark, Wayne county. I have also obtained at Galt, fragments of a species undis- 
tinguishable from this one. 
711. 22. MURCHISONIA LOGANII (». sp.). 
Pl. LXXXIII. Fig. 4 a, b. 
Subfusiform ; spire elongated, consisting of about eleven or twelve volutions, which increase 
somewhat rapidly in size from the apex; last volution expanding towards the aperture; co¬ 
lumella large, without fold or carina ; surface markings unknown. 
This species is readily distinguished from either of the preceding, by the more rapid enlarge¬ 
ment of the volutions, as well as their smaller number. The centre is traversed by a large 
columella, which opens in an expanded umbilicus. I have not been able to discover the evi¬ 
dences of a carina in the moulds, since they are so thickly studded with minute crystals of 
calcareous spar as to obliterate or obscure any such marking. The volutions in the cast are 
more regularly rounded or ventricose than in the preceding species, and, in those I have 
examined, retain no impression of carinse or striae. 
Fig. 4 a. A specimen, the upper part of which is a mould of the shell, while the lower part 
preserves the cast of the interior with some portions of the shell and columella. 
Fig. 4 b. A cast preserving several volutions below the apex. 
Position and locality. In the limestone at Galt, Canada West. 
712. 23. MURCHISONIA MACROSPIRA (n. sp.). 
Pl. LXXXIII. Fig. 5. 
The specimen consists of the mould, showing the impression of four and part of the fifth 
volution, marked by a strong carina along the centre; last volution showing a large canal 
extending downwards in the direction of the spire. 
This species is larger and stronger than the preceding. 
Position and locality. In the limestone at Galt, Canada West. 
