io WATER REPTILES OF THE PAST AND PRESENT 



the rains have washed away and destroyed most of the remains 

 that had been there preserved. Still more fortunate is he if all 

 or nearly all of the original skeleton has been preserved together 

 in its natural relations. After days, perhaps weeks, of labor, the 

 specimen is secured and shipped to the laboratory. Those parts 

 which have been washed out of the chalky rock before the dis- 

 covery of the specimen are always more or less injured and for the 

 most part lost, their fragments strewn down the hillside, for erosion 

 is always slow and many years may have elapsed since first the 

 specimen had appeared at the surface. More frequently, perhaps, 

 a few strokes of the pick and shovel disclose but one, two, or three 

 bones remaining in the rocks. The specimen, if large, or composed 

 of many bones, is carefully uncovered sufficiently to show its extent, 

 and then, so far as possible, removed in large blocks of the rock. 

 The bones themselves, notwithstanding their petrifaction, are 

 usually soft and easily broken, and their separate removal from the 

 matrix may require weeks or even months of labor, work which 

 cannot be done prudently in the field. 



Of many specimens the rock matrix is so hard that the task of 

 removing it from the bones is slow and difficult, indeed well-nigh 

 impossible, for the bones are usually softer than their surrounding 

 matrix. On the other hand, the matrix may be so soft and friable 

 that it cannot be quarried out in blocks. In such cases the separate 

 divisions, as large as they can be excavated and safely handled, 

 are carefully covered with thick bandages of burlap and plaster-of- 

 paris, often strengthened with rods of iron or boards. The skeleton 

 of a single animal treated in this way may require weeks and even 

 months to collect, prepare, and mount in the museum. 



From what has been said the reader will understand how it is 

 possible to make an approximately accurate picture of extinct 

 animals as they appeared in life — approximately accurate, never 

 absolutely so. The flesh and other soft parts of an animal are 

 never petrified, though it is a common belief that they may be. 

 Petrified men and women are still occasionally shown in cheap 

 museums, but they are always frauds. Many times has the writer 

 been called upon to express an opinion as to the nature of seme con- 

 cretion which the discoverer was sure was a petrified snake, turtle, 



