The species of the genus Tachinus (Staphylinidae: Tachyporinae) of North and Central America are revised. Forty-four species are recognized, of which eight are described as new; eight species names are placed in synonymy. The subgenera Drymoporus Thomson and Porodrymus Rey are placed in synonymy with Tachinus and the genus is divided into 17 species groups based on an examination of both the Nearctic and the Palearctic fauna. The distribution of each species is mapped and the male genitalia, the male and female eighth abdominal sternites and tergites, and the male seventh sternite are illustrated for every species. A neotype is designated for T. fumipennis Say, and lectotypes are designated for all the North and Central American species of Tachinus described by Gravenhorst, Erichson, Mäklin, Horn, and Sharp. Diagnostic keys for males and females are included. A brief discussion of the nomenclatural history of the genus, of collecting techniques, and of the major diagnostic characters is included.

The 35 species of the genus Tachyporus Gravenhorst (Staphylindae: Tachyporinae) of North and Central America are revised. Eighteen new species are described: neomexicanus, fenyesi, and howdenorum from the southwestern United States; sharpi from Mexico and the western United States; blomae from Mexico; nigripennis from California; dimorphus, pacificus, and stacesmithi from the Pacific northwest; rulomoides and browni from southeastern Canada and the northeastern United States; and borealis, canadensis, nimbicola, inornatus, ornatus, lecontei, and flavipennis, which are transcontinental in the United States and Canada. Two European species are reported for the first time from North America: abdominalis (Fabricius) and transversalis Gravenhorst. The following new specific synonymy is proposed: tehamae Blackwelder (= californicus Horn); temacus Blackwelder, oregonus Blackwelder, and alleni Blackwelder (= mexicanus Sharp); and acaudus Say, maculipennis LeConte, and chrysomelinus var. infuscatus Bernhauer (= jocosus Say). The genus is divided into 2 subgenera of which Palporus (type species Staphylinus nitidulus Fabricius) is described as new. The subgenus Tachyporus is divided into 12 species groups. Each species is described and its distribution is mapped. The male aedeagus and the pattern of elytral chaetotaxy are illustrated for each species. Major generic characters are illustrated with the aid of scanning electron photomicrographs. Neotypes are designated for the Say species faber, jocosus, and acaudus and lectotypes are designated (when needed) for the North and Central American species described by Erichson, LeConte, Horn, Sharp, and Blatchley and for a variety described by Bernhauer. A diagnostic key for all the species is given.

The species of the genus Sepedophilus (Staphylinidae: Tachyporinae) of America north of Mexico are revised. Thirty species are recognized. Thirteen new species are described: wickhami from the northeastern United States and southeastern Canada; brachypterus, frosti, micans, ctenidialis, and kiteleyi from eastern North America; beckeri from the southcentral United States; and hermani, smetanai, stephani, arizonensis, coronadensis, and velox from the southwestern United States. The following species names are placed in synonymy: knoxii LeConte and carissimus Hatch (= littoreus Linnaeus); imbricatus Casey, limuloides Casey, and elongatus Blatchley (= testaceus Fabricius); corticola Casey (= cinctulus Erichson); virginiae Casey (= velocipes Casey); and subtilis Casey (= debilis Casey). The species cinctulus Erichson and bisignatus Horn, formerly considered as synonyms of opicus Say and bipustulatus Fabricius respectively are recognized as valid species. The Palearctic species marshami Stephens is reported for the first time from the Nearctic region. The usage of the generic group names Sepedophilus Gistel, Conurus Stephens, Conosoma Kraatz, and Conosomus Motschulsky is discussed. The North American species are divided into 12 species groups based on an examination of the Nearctic, Neotropical, and Palearctic faunas. The distribution of each species is mapped, and the male and female eighth abdominal sternites and tergites, the male genitalia and other diagnostic characters, are illustrated. A neotype is designated for Tachyporus opicus Say, and lectotypes are designated when necessary for all the North American species of Sepedophilus described by Gravenhorst, Erichson, LeConte, Horn, and Casey. A diagnostic key for all the species except S. heathi Wasmann is given. A brief discussion of the nomenclatural history of the genus, of collecting techniques, and of the major diagnostic characters is included.

This report presents the field database and analytical results from the Geological Survey of Canada's 2010 to 2012 surficial geology mapping and till sampling campaign in the north Wager Bay project area, mainland Nunavut. An overview of the Quaternary geology of this area is provided together with an interpretation of till provenance, as well as a discussion on the implications for mineral exploration. Field observations and surficial geological mapping indicate the region is key for the glacial history reconstruction of the northeastern part of the Keewatin Sector of the Laurentide Ice Sheet. Most of the study area was located within an extensive onset zone of a large ice stream flowing north into Committee Bay during the last glaciation and early deglaciation, from an ice divide located over and/or south of Wager Bay. Major ice-flow reversals into Repulse Bay and Wager Bay, as a result of drawdown into the opening marine waters in Hudson Bay, are indicated for the latest deglaciation phases. Coldbased ice remnant masses over the uplands north of Wager Bay preserved relict, weathered and fresh glacial landscapes at the end of deglaciation. Although there is evidence of multiple ice-flow directions in the study area, the main ice-flow phase, which converges north (NNE to NNW) towards Committee Bay, is the predominant direction of glacial transport and shaped most prominent streamlined landforms. The carbonate clast content and Al2O3 concentrations in surface till indicates relatively long glacial transport distances linked to glacial dispersal by the ice stream. Mg-rich olivine, many having >Fo90 and high NiO contents, are abundant in till in the center of the study area where a frost-shattered ultramafic lamprophyre boulder was found at the surface. Location of the boulder, its distinctive composition, and the olivine in till distribution in conjunction with the glacial transport history, suggest an ultramafic bedrock source other than kimberlite fields known in the region. In the western part of the study area south of Walker Lake, forsteritic olivine and chromite grains in till, locally coincident with ultramafic boulders, form a 35 km-long NNE dispersal train. This dispersal plume points to olivine-rich crustal rocks within undifferentiated Archean supracrustal rocks, and suggests these rocks have potential to host Ni-Cu-PGE mineralization. In addition to known Penhryn Group rocks and extensions of this belt to the southwest, there are suspected but poorly mapped strands of supracrustal rocks between Beach Pt and Wager Bay which show potential for base- and/or preciousmetal mineralization. More detailed till sampling, prospecting and bedrock mapping is required to better assess mineral potential in these areas.

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