﻿CHAPTER I. 



DISCOVERIES AND COLLECTIONS. 



The silicified trunks of cycads are among the most durable of fossils. Able to 

 resist erosive action indefinitely, and usually occurring in considerable number at 

 the few points where found at all, the unusual outlines of these rare fossils have 

 probably never failed to arrest the attention of the lettered and the unlettered alike, 

 from the remotest antiquity. It is, in fact, quite reasonable to suppose that in 

 anciently settled and populous countries not a few of these fossil plants, so invalu- 

 able to science, have been sequestered and lost — perhaps gathered into cities long 

 since destroyed. The instance of Cycadeoidea etrusca, which was placed on a tomb 

 in the Necropolis at Marzabotto by the Etruscans more than four thousand years ago, 

 and recently refound and described by Capellini & Solms (22)* is well known. 

 Certainly many important specimens have been carried away and lost to view. It 

 is a very suggestive fact that nearly all of the trunks procured from the " Iron 

 Ore Belt" of the Potomac Formation between Baltimore and Washington had been 

 kept by miners and others about their homes, in some instances for quite a hun- 

 dred years (172). But the conditions requisite for silicification must have seldom 

 occurred in geological time, for although the cosmopolitan development of cycadace- 

 ous plants in the middle Mesozoic is well attested by a great abundance of leaves in 

 all plant-bearing strata of late Jurassic or Lower Cretaceous age, wherever found on 

 the globe, the number of silicified cycadean trunks known is so limited as to neces- 

 sitate their being ranked as among the rarest of fossils. Indeed, few good examples 

 have been as yet found beyond the limits of western Europe and southern North 

 America, though they are yet to be expected from all the other continents. The 

 record of fossil cycad discovery and collection is hence in every way an interesting 

 one and may well be dealt with at some length, together with mention of the 

 museums in which the types and important material may be found. 



AMERICAN LOCALITIES AND TYPES. 



MARYLAND. 



The first cycadean trunks from America to receive scientific mention were 

 noticed by Philip Tyson (168) in i860, he having discovered them the previous year 

 in the iron ore beds of the Potomac Formation of Maryland. The original trunks 

 found by Tyson, perhaps ten in number, were all obtained between Baltimore and 

 Washington. Although much discussed at the time, these trunks did not at once 

 receive scientific description, and for twenty-five years remained quite forgotten. A 



r The numbers in parentheses refer to the bibliography at the end of this volume. 



