6 OHIO FOSSILS 



Mix the plaster in a bowl or cup and wash out the container immediately after use, before 

 the plaster hardens in it. To mix plaster, fill the container about half full of water (leave 

 room for the dry plaster) and then drop dry plaster into it slowly with a spoon; do not stir at 

 this point. Let the water soak into the plaster until there is just a little "free" water on top 

 of the mix. Let the mix stand for two minutes or so, then carefully pour off the excess water. 

 Then stir the mix slowly so as not to get bubbles in your plaster. When the mix is like thick 

 cream, pour it slowly into the mold. It is a good idea to pour in a little of the mix and 

 move it about in the mold so that the plaster gets a good start before the rest of it is poured 

 in. Next, pour in enough plaster to fill the mold and allow it to set. Wash out your container 

 and spoon immediately. 



Allow the plaster to set for at least one hour - overnight for a large cast - before 

 attempting to remove the cast from the mold. Pry and tap the cast from the mold slowly and 

 gently around the edges until the crack between the two widens. Strong-arm methods at this 

 point will only result in a broken mold or cast - or both. 



CATALOGUING . A fossil without a label has no scientific value; it is like a letter without 

 an address. Good finds with potentially high scientific value are sometimes spoiled because 

 they are unlabeled. To ensure that your collection will have some scientific use, you should 

 carefully label each lot of fossils in the field. No matter how well you think you know your 

 specimens and where they came from, you will soon forget most of this when other specimens 

 are added to your collection. The field label should have the following information for each 

 lot: a) locality, described exactly, with reference to a map and a landmark (town, river, lake, 

 crossroads; or better, township, county, and state); b) formation if known (see Chapter 2, p. 13 

 for explanation of this term; c) your name; d) the date of collecting. 



When fossils have been cleaned they should be catalogued, even if they cannot be completely 

 identified. A simple catalogue can be made from a bound notebook, so that the pages cannot 

 be lost. The specimens shouldbe numbered consecutively; this can be done with India ink. If 

 the fossil is porous and the ink will not "take" on it, put a dab of clear nail polish on the side 

 away from the specimen or on the poorer side of the specimen if it has no rock clinging to it; 

 let the nail polish dry, then write the number on it with India ink. When the ink is dry, another 

 dab of nail polish on top of the India ink wilL seal it in so that it cannot rub off. 



Enter the numbers in your catalogue and for each one write down its name (if known) and 

 the same information as on the field label (location, formation, collector, and date). 

 Leave a few blank spaces after this for "Remarks" such as "specimen sent to for ident- 

 ification. " If many specimens from a single locality are obviously identical, they may be given 

 the same catalogue number; in that case, enter after "Remarks" the number of specimens in 

 each lot. 



The catalogue is a method of helping out your memory with details about your specimens. 

 It also ensures that specimens will be connected with their exact data in case labels are 

 mixed or specimens are jumbled together by accident. 



BASIC REFERENCES . Remember that this book is only an introduction to the study of 

 fossils. You will want to consult specialized books which are listed in the "References 

 Cited" and referred to by author and year in the text. 



Many publications on fossils have been issued by the Geological Survey of Ohio. They are 

 referred to in the appropriate places in the text. Some of these publications have long been out 

 of print, but others are still available, some free, others at a small charge. The Geological 

 Survey issues a free list of publications (Watkins 1953) available on request, and a bibliography 

 of Ohio Geology (Watkins 1953a). Their geologic map of Ohio (Bownocker, 1920) is indispensable. 

 Books that are out of print can usually be found in public libraries throughout the state. If they 

 are not in your public library, they may be studied in college or university libraries; scarcely 

 a single town in Ohio is more than 50 miles from a college library. Some of these books may 

 be picked up from time to time in second-hand book stores. 



