166 
Fig. 1 shows the half of a cylinder with the divisions, 
which are filled almost homogeneously, so as to appear a 
mere piece of grey marble, the upper end exposing the 
embracing margin of a division in oblong convexities, 
between the angles of which are small remains of the corres- 
ponding folds of the next joints; at the bottom are the con- 
cave sides of the folded margin, the lower corners of which 
are generally left in the angles of the plaits below. Fig. 2 
is turned the other way upwards, and shows its irregular 
cylinder, striae, &c. Fig. 3 a single joint of a larger spe- 
cimen, with part of the shelly covering left; Fig. 4 two 
joints of a smaller specimen broken from No. 5, which 
exposes crystallized Carbonate of Lime in some of 
chambers. 
