Hitchcock's Treptichnid Trace Fossils

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A Bollettino della Società Paleontologica Italiana, 56 (2), 2017, 109-116. Modena

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Hitchcock’s treptichnid trace fossils (Jurassic, Massachusetts, USA): conflicting interpretations in the “Age of Fucoids”

Donald H. Goldstein, Patrick R. Getty & Andrew M. Bush

D.H. Goldstein, Center for Integrative Geosciences, University of Connecticut, 354 Mansfield Road, U-1045, Storrs, Connecticut, 06269, USA; [email protected] P.R. Getty, Center for Integrative Geosciences, University of Connecticut, 354 Mansfield Road, U-1045, Storrs, Connecticut, 06269, USA; [email protected] A.M. Bush, Department of Ecology and Evolutionary Biology and Center for Integrative Geosciences, University of Connecticut, 75 North Eagleville Road, U-3043, Storrs, Connecticut, 06269, USA; [email protected]

KEY WORDS - History of ichnology, Deerfield Basin, Newark Supergroup, burrows, Halysichnus, Treptichnus.

ABSTRACT - Edward Hitchcock was one of the most influential 19th century ichnologists. In a career that lasted nearly three decades, he established 31 invertebrate ichnogenera for Early Jurassic traces from the Hartford and Deerfield Basins of Connecticut and Massachusetts, some of which are in widespread use today. Upon re-examining some of Hitchcock’s specimens, we have identified a number of fossils that are similar to the well-known ichnogenus Treptichnus. Modern ichnologists generally interpret non-marine occurrences of these burrows as the traces of larval insects. In some instances, Hitchcock ascribed his fossils to the activities of annelids or larval insects, and his descriptions of their mode of formation are similar to those presented in much more recent works. However, he also interpreted some treptichnids as algal/ plant fossils. We suspect that his varied interpretations reflect differences in morphology and preservation among specimens. Hitchcock worked in the 19th century, a time known as the “Age of Fucoids”, and his comments also reflect the prevailing uncertainty on trace fossil origins.

RIASSUNTO - [Le tracce fossili treptichnidi di Hitchock (Giurassico, Massachusetts, USA): interpretazioni contrastanti nell’ “Era dei Fucoidi”] - Edward Hitchcock è stato un influente geologo americano del XIX secolo. In una carriera durata quasi tre decenni, scrisse numerosi articoli e pubblicò due volumi fondamentali per la nascente scienza dell’icnologia: “Ichnology of New England” e “Supplement to the Ichnology of New England”. Ha istituito 31 icnogeneri di tracce di invertebrati sulla base di materiale giurassico proveniente dai bacini Hartford e Deerfield (Connecticut e Massachusetts, Stati Uniti). Alcuni di questi icnogeneri sono ampiamente utilizzati ancora oggi. Esaminando la raccolta di Hitchcock, che ha sede presso il Beneski Museum of Natural History (Amherst College) e il Museum of Comparative Zoology (Harvard University), abbiamo identificato diverse tracce simili al noto icnogenereTreptichnus , istituito nel 1889, 25 anni dopo la morte di Hitchcock. Questi campioni sono stati trovati su lastre etichettate ACM ICH 14/4, 16/4, 33/35, 55/20 e MCZ 114312. Al momento della loro descrizione iniziale, Hitchcock ordinò queste tracce in due gruppi. Egli ha attribuito alcuni di questi fossili al suo icnogenere Halysichnus, pensando ad anellidi o insetti larvali come produttori. Le deduzioni di Hitchock non sono lontane dall’attuale interpretazione di queste tane, attribuite dalla maggior parte degli autori al lavoro di insetti larvali. Ha dibattuto, tuttavia, se il secondo gruppo fosse di origine animale oppure se fossero “fucoidi”, ossia piante o alghe fossili. Pensiamo che le sue varie interpretazioni riflettano differenze nella morfologia e nella preservazione delle tracce. Ad esempio, Hitchcock considerava le biforcazioni come una caratteristica di piante e alghe fossili. Di conseguenza, quelle tracce che mostravano biforcazioni erano classificate come fucoidi, mentre quelle che non presentavano questa caratteristica erano considerate tane. I commenti di Hitchock riflettono la sua epoca, nota come “Era dei Fucoidi”, durante la quale le origini di molte tracce fossili erano incerte. A causa della sua prolifica produzione e della volontà di attribuire molte tracce fossili al lavoro di invertebrati, Hitchock può essere considerato come una figura di transizione nella storia dell’icnologia.

INTRODUCTION 1953; Olsen et al., 1998; Olsen & Rainforth, 2003; Getty et al., 2015) have focused on Hitchcock’s vertebrate taxa Edward Hitchcock (1793-1864) was a prolific 19th and have paid little to no attention to traces produced by century geologist at Amherst College in Amherst, invertebrates (for an exception, see Rainforth, 2005). Getty Massachusetts (Anonymous, 1895). He is probably most et al. (2016), however, described the invertebrate burrow well-known for his early ichnological work (Steinbock, Treptichnus, which zigzags and is composed of a series of 1989; Pemberton et al., 2007). During his career, which interconnected segments with projections at the segment spanned nearly three decades, he published two volumes junctions, from a locality in the Hartford Basin near where critical to the early understanding of trace fossils: Hitchcock worked over a century and a half earlier. Ichnology of New England (Hitchcock, 1858a), and To determine whether Hitchcock had observed similar Supplement to the Ichnology of New England (Hitchcock, fossils during his research, we examined specimens at the 1865). In these volumes, he extensively documented the Beneski Museum of Natural History at Amherst College ichnology of the early Mesozoic Hartford and Deerfield and at the Museum of Comparative Zoology at Harvard basins of Connecticut and Massachusetts, USA, and University. We located a number of treptichnids described erected numerous ichnotaxa that are still commonly used by Hitchcock himself, some of which he placed in the today. ichnogenus Halysichnus (Hitchcock, 1858a, b), which Most researchers working in the Hartford and he erected with two ichnospecies: H. laqueatus and H. Deerfield basins subsequent to Hitchcock (e.g., Lull, tardigradus.

ISSN 0375-7633 doi:10.4435/BSPI.2017.11 110 Bollettino della Società Paleontologica Italiana, 56 (2), 2017

Here, we document these specimens and examine The Deerfield Basin is part of the Upper Triassic to Hitchcock’s interpretation of how the fossils were formed. Lower Jurassic Newark Supergroup of eastern North In recent literature, non-marine treptichnids have been America, which formed as Pangea fragmented and the attributed to the activity of insects, particularly larval incipient Atlantic Ocean formed (Olsen, 1978; Olsen et flies (Seilacher, 1955; Bajard, 1966; Tessier et al., 1995; al., 1992). In the Late Triassic, coarse fluvial sediment Uchman, 2005; Martin, 2009; Muñiz Guinea et al., 2014). of the Sugarloaf Formation was deposited. In the Early However, in the 1850s, the origins of these and other Jurassic, however, crustal extension rates increased and traces were much more uncertain, and many trace fossils border faults on the eastern edge of the basin coalesced to were described as fossilized algae, or “fucoids” (Osgood, form an asymmetrical, east-dipping half graben (Schlische 1975). Hitchcock’s various writings illustrate the tension & Olsen, 1990). Accordingly, lacustrine sedimentation between these competing views of trace fossil genesis in commenced as fine-grained sediments of the Fall River the mid-19th century. Beds and Turners Falls Formation were deposited. The lake deposits exhibit cyclically alternating layers of gray to black shale formed in deep, permanent bodies of water and GEOLOGICAL CONTEXT red mudstone and sandstone formed in playas. Olsen (1986) attributed these cycles to Milankovich cycle-influenced The specimens that Hitchcock described were found climate changes. Models indicate that the paleoclimate of at four of his classic localities: Turners Falls, the Lily the Deerfield basin was monsoonal (Parrish, 1993), and Pond, Field’s Orchard, and Field’s Farm (Hitchcock, sedimentological evidence indicates that there was a long 1858a, b, 1865), all of which are in the Deerfield Basin of dry season (Hubert, 1978). The increased crustal extension northwestern Massachusetts, USA (Fig. 1a-b). The rock in the Early Jurassic also led to widespread volcanism from all four sites is derived from the Lower Jurassic during a 600 ky period throughout Pangea (Olsen et al., Turners Falls Formation, which is 2 km thick and consists 1996); the local lava flows are known as the Deerfield of playa/playa lake redbeds and gray to black lacustrine Basalt. Sedimentation in the basin is thought to have ceased strata, along with minor fluvial strata (Olsen et al., 1992; by the Middle Jurassic (Olsen et al., 1992). Hubert & Dutcher, 2005; Fig. 1c). The slabs on which the fossils are preserved were most likely derived from the shallow lacustrine facies of the formation, as determined MATERIALS AND METHODS by the light brown to gray color of the rock and the presence of dinosaur tracks on some of the slabs. We examined specimens in the Ichnology Collection at the Beneski Museum of Natural History at Amherst College (ACM ICH) and the Invertebrate Paleontology Collection at the Museum of Comparative Zoology at Harvard University (MCZ). Treptichnids were located on the following slabs: ACM ICH 14/4, 16/4, 33/35, 55/20, and MCZ 114312. They were photographed under low-angle light and measurements were taken from the photographs using the public-domain image- processing and analysis program ImageJ (Rasband, 1997-2014). Hitchcock’s interpretations of these traces were ascertained from his published works (Hitchcock, 1858a, 1865), as well as unpublished manuscripts (Hitchcock, 1858b, 1862a, b) in the Amherst College Special Collections. Additional historical information on the drawings and sketches were obtained from the Linda Hall Library Digital Collections.

SPECIMEN DESCRIPTIONS

ACM ICH 14/4 (Fig. 2) Numerous burrows are preserved in concave epirelief on a slab of red shale, measuring approximately 5.6 m by 1.6 m, which also exhibits dinosaur tracks, mud cracks, and carbonate nodules. Eight of these traces were analyzed in detail and two distinct morphologies were observed. Fig. 1 - Geological and geographical context. a) Sketch map of North The first trace morphology (Fig. 2a) has relatively long America with the field region, in the northeast of the United States, 3.4-16.7 mm (mean 10 mm), straight segments ranging shaded in black. b) Close-up of southern New England showing from 0.7-1.6 mm (mean 1.5 mm) wide. The projections, the distribution of Mesozoic rocks in gray and black. The fossils described herein are from the town of Turners Falls, Massachusetts. where present, extend up to 1.4-3.4 mm from the Abbreviations are as follows: CT, Connecticut; MA, Massachusetts; segment junction and are not expanded and bulblike. RI, Rhode Island. c) Simplified stratigraphic column of the Deerfield These burrows exhibit meandering or looping paths and basin. The fossils are from the Turners Falls Formation. have angles between the segments from 108°-178°. The D.H. Goldstein et alii - Hitchcock’s Treptichnids 111

in bulbous projections that extend 0.7-2.4 mm beyond the segment juncture and are 0.7-1.7 mm wide. Angles between segments range from 75°-174°. These traces have a meandering, curved, or looping path.

ACM ICH 16/4 (Fig. 3a) Two burrows are preserved, along with dinosaur tracks, in concave epirelief on a slab of gray shale that measures 1.4 m by 0.6 m. The shorter trace consists of three segments and has a curved course, whereas the longer trace is composed of approximately 16 segments (it is partly obscured by the overprinting of dinosaur tracks) and has a meandering course. Segments vary in length from 18-42 mm long and in width from 2.7-4.4 mm. The Fig. 2 - Two of Hitccock’s “fucoids” on ACM ICH 14/4. a) traces change direction at the segment junctures, which Specimen with long, straight segments that lacks expanded bulbous are sometimes slightly expanded relative to the rest of the terminations. b) Specimen with relatively short segments and segment, but no projections are present. Angles between expanded, bulbous terminations. Compare these specimens to those segments range from 109°-162°. in Fig. 5. Scale bars are 10 mm. ACM ICH 33/35 (Fig. 3b-c) A segmented, shallow burrow is preserved, along with second morphology (Fig. 2b) consists of relatively short poorly defined dinosaur tracks, on a slab of gray shale (2.3-6.6 mm long; mean 3.3 mm), thin (0.3-2.0 mm; measuring 89 cm by 31 cm. The burrow occurs in convex mean 1.2 mm) interconnected segments that terminate epirelief along most of its length, but in a few places

Fig. 3 - Hitchcock’s ichnospecies Halysichnus laqueatus. a) Shallowly impressed specimen (arrowed) on ACM ICH 16/4. b) Lectotype specimen on ACM ICH 33/35. Note the bilobate appearance. c) Tracing of Hitchcock’s (1858) interpretive sketch of the lectotype specimen. d) Specimen on ACM ICH 55/20. Scale bars are 10 mm. 112 Bollettino della Società Paleontologica Italiana, 56 (2), 2017 as a concave epirelief where the infill has spalled away measuring 25.9 cm by 13.8 cm. The burrow begins with from the slab. The burrow is composed of approximately two tight loops, after which it maintains a nearly straight to 26 segments that are characteristically bilobed due to a slightly sinuous path for approximately 16 cm. It is preserved furrow running down their midline. Segment junctures in convex hyporelief where the segments remain attached are slightly wider than the segments themselves and to the overlying slab, and in concave hyporelief where the occur as small depressions or raised mounds. Individual segments have spalled away. At many locations along the segments measure 0.9-1.6 cm long by 2.5-3.4 mm wide. length of the burrow the tips of the segments preferentially Angles between the segments range from 87°-169°. The remained attached whereas the remainder of the segments burrow path is looped in two places that are separated by spalled away, giving those portions of the burrow the a straight section. appearance of a linear series of raised bumps. There are 59 segments ranging in length from 4.1-9.8 mm, and in width ACM ICH 55/20 (Fig. 3d) from 0.9-1.6 mm. Projections, which are slightly wider than One segmented, looping trace preserved in concave the remainder of the segments and measure 1.3-2.8 mm epirelief occurs on a slab of brown shale measuring 6.9 in length, are clearly visible at some of the junctures. The cm by 5.0 cm. The trace consists of nine segments, at projections exhibit an alternating left to right pattern along the juncture of which the trace changes direction. Angles some parts of the burrow length, but at others, both around between segments range from 93°-171°. Short projections curves and in straight portions of the burrow path, they occur of up to 1.3 mm occur at some of the junctures, some of on one side. Angles between segments range from 128°-177°. which are slightly expanded relative to the rest of the segments. Individual segments measure 8.0-9.0 mm long and 1.0-1.8 mm wide. DISCUSSION

MCZ 114312 (Fig. 4) Hitchcock’s fossils as treptichnids A single segmented burrow is preserved on a slab Miller (1889) erected the ichnogenus Treptichnus (which Rainforth [2005] had assumed was lost) of red shale for zigzagging traces that had projections at the angled

Fig. 4 - Hitchcock’s ichnospecies Halysichnus tardigradus. a) Complete specimen, previously assumed lost (Rainforth, 2005), on MCZ 114312. b) Close-up of the looped portion of the trace, showing one of the segments that compose the trace (upper arrow), and how the segments preferentially spall away (lower arrow) to make the trace look like a series of bumps. c) Hitchcock’s interpretive sketch of the complete specimen. Scale bars are 10 mm. D.H. Goldstein et alii - Hitchcock’s Treptichnids 113 turns. Nearly a century later, Archer & Maples (1984) and Maples & Archer (1987) reexamined Treptichnus, along with other ichnogenera Miller established from the same region, and concluded that the traces were segmented burrows that had slight upturns at the end of each segment that communicated with the sediment surface. Getty et al. (2016) examined a large suite of Treptichnus from the East Berlin Formation of Holyoke, Massachusetts, and concluded that the specimens represented extremely shallow burrows produced in mud laminae that draped cross-bedded sandy layers. The Holyoke specimens varied widely in morphology; some burrows had long, straight segments, while others had short segments with bulbous terminations (Fig. 5). Many of the specimens described by Getty et al. (2016), as well as other treptichnids reported from the Newark Supergroup (e.g., Metz, 2007), are Fig. 5 - Treptichnids found in Holyoke, Massachusetts from a site similar to the specimens described by Hitchcock (e.g., near where Hitchcock worked. a) Burrow composed of long, straight Figs 2a-b, 3d, 4). Given that the specimens are shallowly segments lacking terminal expansions. b) Burrow composed of emplaced, segmented burrows with angled turns at relatively short segments with expanded, bulbous terminations. The the junctions, Hitchcock’s specimens are considered specimens from this locality were described by Getty et al. (2016). treptichnids herein. Scale bars are 10 mm. Hitchcock (1858a, b) assigned most of his treptichnid specimens to the ichnogenus Halysichnus and its two ichnospecies, H. laqueatus and H. tardigradus. He Hitchcock’s views on the origin of the traces considered the latter ichnospecies to be distinct in that it The 19th century has been described as the “Age of was smaller, and had shorter segments, than the former Fucoids”, a time during which many animal trace fossils ichnospecies. His descriptions and illustrations (Figs were interpreted as the remains of plants or algae (Osgood, 3c, 4c) of the burrows within these ichnospecies were 1975). For example, Marché (1992) noted that Hitchcock poor, however, by his own admission. They did not show (1841) had described, as a fossil alga, an invertebrate many characteristic traits of the fossils, especially the burrow that was later named Scoyenia by White (1929). overlapping burrow segments and projections. As a result, Examination of Hitchcock’s published and unpublished his work on these fossils has been largely overlooked writings reveals some confusion in his interpretation of by subsequent workers. For example, Miller (1889) did treptichnid fossils as well, although some were interpreted not recognize the similarities between the fossils that he as invertebrate burrows, others were interpreted as plant described as Treptichnus and those described by Hitchcock remains (Hitchcock, 1862a). as Halysichnus. Additionally, Häntzschel (1975) Hitchcock identified specimens on slabs ACM ICH considered Hitchcock’s description and illustrations 16/4, 33/35, 55/20, and MCZ 114312 as animal traces so inadequate that he included Halysichnus in a list of and erected the taxon Halysichnus for them. He described unrecognizable ichnogenera. Halysichnus as a “Trackway with ridges on each side; Here, we have redescribed and reillustrated Hitchcock’s as if the animal had ploughed its way through the mud two ichnospecies of Halysichnus, which will serve as a instead of gliding over the surface; crossed at intervals by basis for comparing the ichnogenus to others. Most depressions, giving the appearance of a chain” (Hitchcock, importantly, some specimens of Halysichnus, including the 1858a, p. 162; 1858b, p. 597). Hitchcock’s description lectotype (ACM ICH 33/35) of the type ichnospecies H. of Halysichnus as a shallow burrow with openings (i.e., laqueatus, appear very similar or identical to Treptichnus. depressions) is similar to that of treptichnids from the We thus consider Halysichnus to be the senior synonym of Hartford Basin described by Getty et al. (2016). The Treptichnus. Considering that Treptichnus has been a much similarity is even more pronounced when one considers more widely used name than Halysichnus, however, rigidly that chains are made of links, or segments, as are applying the Principle of Priority to replace Treptichnus treptichnids. Hitchcock attributed the ichnogenus to an with Halysichnus would cause significant disruption in annelid tracemaker, although he was aware that other the literature. The ICZN (Ride et al., 1999) provides two invertebrates, such as insect larvae, “move forward in criteria which, if met, can justify a reversal of precedence the same manner” (Hitchcock, 1858a, p. 163; 1858b, p. and the retention of a junior synonym. These include the 598). Thus, he entertained the possibility of larval insect senior synonym not having been used as a valid name after tracemakers forming shallow burrows, similar to modern 1899, and the use of the junior synonym by at least ten interpretations of treptichnids (Seilacher, 1955; Bajard, authors in at least 25 works published within a ten-year 1966; Tessier et al., 1995; Uchman, 2005; Martin, 2009; span in the preceding 50 years. A cursory literature search Muñiz Guinea et al., 2014; Getty et al., 2016). demonstrates that the second criterion is satisfied, but Hitchcock (1865) however, in Appendix B, which is Halysichnus was used in Hitchcock (1927), and therefore credited to his son Charles, referred to the treptichnids the first criterion has not been met. Consequently, the on slab ACM ICH 14/4 as being “apparently of vegetable matter must be referred to the Commission of Zoological origin” (p. 50). In the unpublished 1862 draft of this Nomenclature for a ruling, before which time the usage appendix, Edward referred to these fossils as “fucoidal of Treptichnus can be maintained. impressions and probably several rows of the tracks of 114 Bollettino della Società Paleontologica Italiana, 56 (2), 2017

Fig. 6 - A portion of a page from C.H. Hitchcock’s (1863) draft of the Supplement to the Ichnology of New England in which he first refers to the treptichnids as “rows of the tracks of small crustaceans or annelids”, but then replaces the text with “trails apparently of vegetable origin”. small crustaceans or annelids” (Hitchcock, 1862b, Book Reaction” (Baucon et al., 2012), in which fucoids were 1, p. 29). Charles Hitchcock (1863, p. 17) later refers to reinterpreted as trace fossils, by over 20 years. the treptichnids as “rows of the tracks of small crustaceans or annelids”, which is then crossed out and replaced with “trails apparently of vegetable origin” (Fig. 6). Clearly, CONCLUSIONS Edward and Charles (who was assisting his father due to illness) were struggling with competing interpretations Edward Hitchcock examined numerous specimens of these fossils and vacillated on what to call them. It is of treptichnid trace fossils from the Lower Jurassic of not clear whether this change was made independently Massachusetts. He placed some of these in the ichnogenus by Charles Hitchcock, or in consultation with Edward Halysichnus, but the similarities between this taxon and Hitchcock, and there is no indication in Edward Treptichnus were not clear due to the lack of detail in Hitchcock’s letters or unpublished drafts clarifying this Hitchcock’s illustrations. Hitchcock variously interpreted question. We are left with a mystery that is unlikely to these fossils as representing invertebrate traces or the be resolved. remains of plants or algae (“fucoids”). We suggest that his So why did Hitchcock interpret some of these traces confusion resulted in part from variations in morphology as burrows and others as fucoids? This question can be and preservation among specimens. His struggles to answered by comparing the mode of preservation and interpret these burrows embody the uncertainties faced morphology among the two groups of fossils. Most of by trace fossil workers in the mid-19th century. the specimens that he considered burrows (e.g., ACM ICH 33/35, 55/20, MCZ 114312) are preserved in three dimensions with the burrow fill intact, whereas ACKNOWLEDGEMENTS those that he interpreted as fucoids were preserved in concave epirelief on the top of ACM ICH 14/4. Thus, This work is a contribution to the call for papers arising from this latter group could be interpreted as external molds the Fourth International Congress on Ichnology “Ichnia 2016 - st of plant remains. More importantly, however, Hitchcock Ichnology for the 21 century: (palaeo)biological traces towards describes fucoids as having a “bifid or trifid appearance” sustainable development”, held in Idanha-a-Nova (Portugal), 6-9 May 2016. (Hitchcock, 1858a, p. 170). The treptichnids on ACM ICH Mr. Goldstein would like to dedicate this work to the memory 14/4 exhibit clear projections and bifurcations (Fig. 2), of his friend, David P. Zynda. We thank Kate Wellspring and Hayley whereas in those that he correctly interpreted as burrows Singleton (Beneski Museum of Natural History, Amherst College) these features are generally lacking (ACM ICH 16/4, and Jessica Cundiff (Museum of Comparative Zoology, Harvard 33/35, 55/20), or they were obscured by preservation University) for access to Hitchcock’s specimens and information on (MCZ 114312). The presence or absence of projections in their history. We are also grateful to the Amherst College Museum of other treptichnids has been interpreted as being the result Arts Special Collections for access to historical documents written of variations in the plane of section of the burrow (e.g., by Edward, Orra White, and Charles Hitchcock. Additional access to Archer & Maples, 1984), or behavioral variations among historical documents was provided by the Linda Hall Library digital collections. We appreciate the kind generosity of Gabriella Mángano individuals (e.g., Getty et al., 2016). and Luis Buatois for sending photographs of Treptichnus specimens. In speaking of invertebrate traces, Hitchcock (1858b, We would also like to thank Sören Jensen and an anonymous p. 587) noted that some “are not a little anomalous”. He reviewer for helpful comments on the manuscript. Finally, we also stated that they “so closely resemble certain ribbon- thank the conveners of the Ichnia 2016 conference in Portugal for like fucoids, or sea-weeds, that I have found it difficult to their invitation to present this work and contribute to this volume. distinguish between them” (1858a, p. 170). Treptichnid burrows illustrate this quandary perfectly, since Hitchcock described some preservational/morphological variants REFERENCES as animal traces and others as plants. Having interpreted Anonymous (1895). Edward Hitchcock. Popular Science Monthly, some of these fossils as animal burrows, and having 47: 689-696. erected the ichnogenus Halysichnus three decades prior Archer A.W. & Maples C.G. (1984). Trace fossil distribution to Miller’s (1889) erection of Treptichnus, Hitchcock across a marine-to-nonmarine gradient in the Pennsylvanian of anticipated the “Period of Controversy”, or “Age of southwestern Indiana. Journal of Paleontology, 58: 448-466. D.H. Goldstein et alii - Hitchcock’s Treptichnids 115

Bajard J. (1966). Figures et structures sédimentaires dans la zone Martin A. (2009). Neoichnology of an Arctic fluvial point bar, North intertidale de la partie orientale de la baie du Mont-Saint-Michel. Slope, Alaska (USA). Geological Quarterly, 53: 383-396. Revue de Géographie physique et de Géologie dynamique, 8: Metz R. (2007). Late Triassic invertebrate trace fossils from 39-111. lacustrine shoreline deposits, Smith Clark Quarry, Milford, Baucon A., Bordy E., Brustur T., Buatois L.A., Cunningham T., New Jersey. Northeastern Geology & Environmental Sciences, De C., Duffin C., Felletti F., Gaillard C., Hu B., Hu L., Jensen 29: 1-14. S., Knaust D., Lockley M., Lowe P., Mayor A., Mayoral E., Miller S.A. (1889). North American Geology and Paleontology. Mikuláš R., Muttoni G., Carvalho C.N., Pemberton G.S., Pollard 793 pp. Western Methodist Book Concern, Cincinnati, Ohio. J., Rindsberg A.K., Santos A., Seike K., Song H.-b., Turner S., Muñiz Guinea F., Mángano M.G., Buatois L.A., Poeniene V., Uchman A., Wang Y.-y., Yi-ming G., Zhang L. & Zhang W.-t. Gámez Vintaned J.A. & Mayoral Alfaro E. (2014). Compound (2012). A History of Ideas in Ichnology. In Knaust D. & Bromley biogenic structures resulting from ontogenic variation: R.G. (eds), Developments in Sedimentology, 64: 3-43. An example from a modern Dipteran. Spanish Journal of Getty P.R., Hardy L. & Bush A.M. (2015). Was the Eubrontes track Paleontology, 29: 83-94. maker gregarious? Testing the herding hypothesis at Powder Olsen P.E. (1978). On the use of the term Newark for Triassic and Hill Dinosaur Park, Middlefield, Connecticut. Bulletin of the Early Jurassic rocks of eastern North America. Newsletter of Peabody Museum of Natural History, 56: 95-106. Stratigraphy, 7: 90-95. Getty P.R., McCarthy T.D., Hsieh S. & Bush A.M. (2016). A new Olsen P.E. (1986). A 40-million-year lake record of early Mesozoic reconstruction of continental Treptichnus based on exceptionally orbital climactic forcing. Science, 234: 842-848. preserved material from the Jurassic of Massachusetts. Journal Olsen P.E., McDonald N.G., Huber P. & Cornet B. (1992). of Paleontology, 90: 269-278. Stratigraphy and Paleoecology of the Deerfield rift basin Häntzschel W. (1975). Trace fossils and problematica. In Teichert C. (Triassic-Jurassic, Newark Supergroup), Massachusetts. In (ed.), Treatise on Invertebrate Paleontology, Pt. W, Miscellanea, Robinson P. & Brady J.B. (eds), Guidebook for Field Trips in supplement 1, The Geological Society of America and The the Connecticut Valley Region of Massachusetts and Adjacent University of Kansas: W2-W269. States, volume 2. New England Intercollegiate Geological Hitchcock C. (1863). Appendix B, Descriptive Catalogue of the Conference 84th Annual Meeting, Department of Geology Specimens in the Hitchcock Ichnological Cabinet of Amherst and Geography, University of Massachusetts, Amherst, College. Unpublished draft. 92 pp. Amherst College Archives Massachusetts: 488-535. and Special Collections. (Box 13, folder 5). Accessed July 16, Olsen P.E. & Rainforth E.C. (2003). The Early Jurassic Ornithischian 2016. Online Access: https://acdc.amherst.edu/view/asc:74473/ dinosaurian ichnogenus Anomoepus. In LeTourneau P.M. & asc:74474 Olsen P.E. (eds), The Great Rift Valleys of Pangea in Eastern Hitchcock C. (1927). The Hitchcock lecture upon ichnology and the North America, Volume 2: Sedimentology, Stratigraphy, and Dartmouth College Ichnological Collection. American Midland Paleontology, Columbia University Press: 313-367. Naturalist, 10: 161-197. Olsen P.E., Schlische R.W. & Fedosh M.S. (1996). 580 ky duration Hitchcock E. (1841). Final Report on the Geology of Massachusetts. of the Early Jurassic flood basalt event in eastern North America 831 pp. J.H. Butler, Northampton. estimated using Milankovitch cyclostratigraphy. In Morales M. Hitchcock E. (1858a). Ichnology of New England, a Report on (ed.), The Continental Jurassic. Museum of Northern Arizona the Sandstone of the Connecticut Valley, Especially its Fossil Bulletin, 60: 11-22. Footmarks. 327 pp. William White, Boston. Olsen P.E., Smith J.B. & McDonald N.G. (1998). Type material Hitchcock E. (1858b). Ichnology of New England, a Report on of the type species of the classic theropod footprint genera the Sandstone of the Connecticut Valley, Especially its Fossil Eubrontes, Anchisauripus, and Grallator (Early Jurassic, Footmarks. Unpublished draft. 698 pp. Amherst College Hartford and Deerfield Basins, Connecticut and Massachusetts, Archives and Special Collections, (Box 12, folders 9-17). U.S.A.). Journal of Vertebrate Paleontology, 18: 586-601. Hitchcock E. (1862a). Supplement to the Ichnology of New England. Osgood R.G., Jr. (1975). The history of invertebrate ichnology. Unpublished draft of a speech read before the Academy of Arts In Frey R. (ed.), The Study of Trace Fossils: A Synthesis of and Sciences, Boston, Dec. 9, 1862. 20 pp. Amherst College Principles, Problems, and Procedures in Ichnology, Springer- Archives and Special Collections, (Box 13, folder 1). Online Verlag: 3-12. access: https://acdc.amherst.edu/view/asc:78832/asc:78833 Parrish J.T. (1993). Climate of the supercontinent Pangea. Journal Hitchcock E. (1862b). Descriptive Catalogue of the Fossil of Geology, 101: 215-233. Footmarks in the Ichnological Cabinet of Amherst College. Pemberton S.G., Gingras M.K. & MacEachern J.A. (2007). Edward Unpublished draft. 119 pp. Amherst College Archives and Hitchcock and Roland Bird: Two early titans of vertebrate Special Collections. ( Pratt Museum Papers, Box X, folder 7A). ichnology in North America. In Miller W. (ed.), Trace Fossils: Hitchcock E. (1865). Supplement to the Ichnology of New England. Concepts, Problems, Prospects, Elsevier: 32-51. A Report to the Government of Massachusetts, in 1863. 96 pp. Rainforth E.C. (2005). Ichnotaxonomy of the fossil footprints of Wright and Potter, Boston. the Connecticut Valley (Early Jurassic, Newark Supergroup, Hubert J.F. (1978). Paleosol caliche in the New Haven Arkose, Newark Connecticut and Massachusetts). 1301 pp. Unpublished Ph.D. Group, Connecticut. Paleogeography, Palaeoclimatology, thesis, Columbia University. Palaeoecology, 24: 151-168. Rasband W.S. (1997-2014). ImageJ: U.S. National Institutes of Hubert J.F. & Dutcher J.A. (2005). Synsedimentary sand pillows of Health, Bethesda, Maryland, USA. URL http://imagej.nih.gov/ a lacustrine delta slope (Turners Falls Formation) and sheetflood ij/, March 2015. deposition of alluvial-fan gravels (Mount Toby Formation), Ride W.D.L., Cogger H.G., Dupuis C., Kraus O., Minelli A., Early Jurassic Deerfield Basin, Massachusetts. Northeastern Thompson F.C., & Tubbs P.K. (1999). International Code of Geology & Environmental Sciences, 27: 18-36. Zoological Nomenclature Fourth Edition. The International Lull R.S. (1953). Triassic Life of the Connecticut Valley. 336 pp. Trust for Zoological Nomenclature: online (incorporating 2012 Connecticut State Geological and Natural History Survey, Hartford. amendments) http://iczn.org/iczn/index.jsp. Maples C.G. & Archer A.W. (1987). Redescription of Early Schlische R.W. & Olsen P.E. (1990). Quantitative filling model Pennsylvanian trace-fossil holotypes from the nonmarine for continental extensional basins with applications to early Hindostan Whetstone Beds of Indiana. Journal of Paleontology, Mesozoic rifts of eastern North America. Journal of Geology, 61: 890-897. 98: 135-155. Marché J.D. II. (1992). Edward Hitchcock, Fucoides, and the Seilacher A. (1955). Spuren und Fazies im Unterkambrium. In ichnogenus Scoyenia. Earth Sciences History, 11: 13-20. Schindewolf O.H. & Seilacher A. (eds), Beiträge zur Kenntnis 116 Bollettino della Società Paleontologica Italiana, 56 (2), 2017

des Kambriums in der Salt Range (Pakistan). Akademie der Footprints in the Black Warrior Basin of Alabama. Alabama Wissenschaften und der Literatur zu Mainz, Abhandlungen der Paleontological Society Monograph, 1: 143-146. mathematisch- naturwissenschaftliche Klasse, 10: 373- 399. White C.D. (1929). Flora of the Hermit Shale, Grand Canyon, Steinbock R.T. (1989). Ichnology of the Connecticut Valley: A Arizona. Carnegie Institute Washington Publication, 405: vignette of American science in the early Nineteenth Century. 1-221. In Gillette D.D. & Lockley M.G. (eds), Dinosaur Tracks and Traces, Cambridge University Press: 27-32. Tessier B., Archer A.W., Lanier W.P. & Feldman H.R. (1995). Comparison of ancient tidal rhythmites (Carboniferous of Kansas and Indiana, USA) with modern analogues (the Bay of Mont-Saint-Michel, France). Special Publications International Association of Sedimentologists, 24: 259-271. Manuscript received 13 December 2016 Uchman A. (2005). Treptichnus-like traces made by insect Revised manuscript accepted 7 March 2017 larvae (Diptera: Chironomidae, Tipulidae). In Buta R.J., Published online 4 August 2017 Rindsberg A.K. & Kopaska-Merkel D.C. (eds), Pennsylvanian Guest Editors Andrea Baucon & Carlos Neto de Carvalho