Abstract Fossil trackways in the Jura-Triassic rift basin of the Connecticut River Valley are important to geoheritage for their quality, preservation, and role in the history of geology, especially of ichnology. Discovered in the early 1800s, these trackways of small to large, bipedal, three-toed animals came to the attention of Edward Hitchcock, a prolific geologist and natural theologian. His first publication on the subject was in January 1836 and, in the same year, William Buckland included parts of the report, with illustrations, in his Bridgewater Treatise. Hitchcock and Buckland are credited with establishing the field of ichnology, the study of track and trails. Within the first decade, other traces documented include four-footed tracks, fish fossils, invertebrate burrows, plant impressions, ripple marks and raindrop impressions; few bones have ever been discovered in the valley. Early fossil-track collectors included Hitchcock, James Deane, Dexter Marsh and Roswell Field. Specimens quickly made their way to Europe, and publications brought the tracks to international attention, in both science and literature. In nineteenth-century discussions, the three-toed trackway makers – birds or dinosaurs? – were particular subjects of interest and debate. These fossil trackways remain well known and studied today, with several preserved field sites and museum collections.

Abstract Organic matter is a ubiquitous component of siliciclastic sediments and sedimentary rocks. It ranges in abundance from a major component, constituting more thn 30 percent of some sapropelic shales to less than 0.1 percent of certain marine red beds. The following table, derived from Ronov (1958), Yemel'Yanov (1975), Dean and Gardner (1982), and D. L. Gautier and T. R. Walker (unpublished data) illustrates the range of organic carbon (C org ) in siliciclastic sediments: Fine-grained marine sediments contain two principal types of organic matter (Fig. 1-1). The first is derived from marine phytoplankton that live in the photic zone of the marine water column; Type II kerogen in the classification of Tissot et al. 1974. This organic matter consists largely of the remains of unicellular algae, which decompose to yield hydrogen-rich, sapropelic material. If preserved in the sedimentary record in sufficient quantities, type II kerogen may serve as a source for oil generation. This type of organic matter is highly reactive, readily consumed by both aerobic and anerobic organisms, and subject to rapid decomposition in oxygenated environments. The second organic-matter type found in most marine sediments is terrigenous organic material (type III kerogen) derived mainly from higher land plants and transported through rivers and by marine currents to the sites of deposition. Terrigenous organic matter is greatly depleted in hydrogen relative to marine organic matter (Fig. 1-1). It is thus much less readily consumed by aerobic and anaerobic organisms than is type II. Similarly, type III is more refractory during burial diagenesis

Abstract Aquatic nonmarine (i.e., fresh water) deposits can be conveniently subdivided into lotic (running water) and lentic (standing water) environments. Rivers, streams and wave-swept beaches of lakes are mostly lotie; while ponds, lakes and pools are lentic. Such environments often are characterized mistakenly as being devoid of trace-making organisms, and, in many cases, this trait has been utilized to distinguish fresh water from marine deposits in the rock record. However, contrary to this popular belief, modern fluvial and lacustrine environments commonly are inhabited by a diverse assemblage of infaunal and epifaunal organisms, which can and do create preservable biogenic structures. Little ichnologic work has been done in modern aquatic nonmarine deposits. Recently, however, significant strides have been made to better understand the animal-sediment relationships of such environments (e.g., see Chamberlain, 1975a; Meichior and Ericson, 1979; Fisher, Lick, McCall and Robbins, 1980; Ratcliffe and Fagerstrom, 1980; McCall and Tevesz, 1982; Fisher, 1982; Cohen, 1984). The physical characteristics of freshwater environments are fairly well known. Fluvial deposits have received in-depth study, and a number of facies models, including characteristic vertical sequences, have been erected (e.g., see Collinson, 1978; Cant, 1982). Lacustrine environments, on the other hand, are much more enigmatic; however, criteria for their recognition have been summarized by several workers (e.g., see Picard and High, 1972; Collinson, 1978b; Pouch and Dean, 1982. As is the case with marine environments, ichnologic investigations of fresh water deposits have proceeded from two main directions: (1) study of Holocene traces, the organisms that produce them, and