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The greatest diversity of Cenozoic crocodilians occurred during the Miocene in equatorial South America. However, the origin of this high diversity and its relationship to environmental factors are poorly understood. Most described species come from localities assigned to Laventan (13.8-11.8 Ma) and Huayquerian (9.0-6.8 Ma) South American land mammal ages (SALMAS), whereas the record is sparse in the early to middle Miocene and after the latest Miocene and Pliocene. Field research in the Castilletes (early Miocene-Pliocene) Formation in the High Guajira Peninsula of Colombia provides new fossil data on the origin of Neotropical crocodylian diversity. The Castilletes Formation crops out most extensively in the Cocinetas Basin, and represent depositional environments consisting of deltaic and shallow marine systems in the lower Castilletes and predominately fluvial environments in the upper Castilletes. Crocodilian fossils from the Castilletes Formation include gavialoids, alligatoroids and crocodyloids. Gavialoid remains have been recovered from both terrestrial and shallow marine deposits in the lower Castilletes. Remains of the specialized caimanines Purussaurus and Mourasuchus extend the temporal range of both lineages into the early middle Miocene (15-16 Ma). These records suggest that high diversity crocodilian assemblages were already established by the early Miocene or late Oligocene. Fossils from the upper Castilletes Formation include cranial elements identified as a non-tomistomine crocodyloid, some of them assigned to cf. Crocodylus. These records indicate that by the Pliocene, endemic assemblages were extinct, at least in the northern parts of the continent, allowing the establishment of Crocodylus. The pattern of crocodilian diversity in the Neogene of equatorial South America suggests that diversity was highly linked to hydrographic conditions. The development of high diversity assemblages developed in a time of greater connections among river drainages and mega-wetland systems. The isolation of river drainages and disappearance of mega-wetlands are correlated with the extinction of most crocodilian lineages. Aridity in peripheral drainages may have caused local extinctions outside Amazonia. The change from wetland to riverine conditions has been proposed as the cause of crocodilian extinctions in the western Amazon, but this remains to be tested. Advisor: Jason Head

Light, Space, Color, and texture are elements often used in the construction of Architectural composition. This thesis is about adding sound (noise) to that palette.

This thesis is about learning from architecture, it is about teaching design at an early age, and how light and space speak about architecture. It is about teaching design and architecture at the high school level, and the ideas, metaphors and sources of inspirations used to achieve this. Design students require a sense of the sublime, the ability to respond to art and architecture, and challenge to aspire to greatness. Schools of design must teach about nature, the metaphysical and the fragility of mankind, moving away from prior schools of thought including "form follows function" and replacing the traditional teaching of architecture with a more inclusive approach.One way to develop thought processes that lead to inclusivity is through the metaphor. Metaphors are the foundation of the imagination. Strongly developed metaphorical channels are essential to any designer. They offer opportunities to contemplate a proposed work in another light. They inspire the designer to probe new sets of questions and develop new ideas and interpretations. Several metaphors formed the basis of this thesis, "Learning as Light," "A new light every dawn," and "Education by Design," which proposes that twenty?first century design educators rely more greatly on the use of metaphors in their teaching curriculum. Above all, the search for the metaphysical "soul of the building" is and will continue to be the most integral element in the teaching of design and architecture. Art, architecture and archeology are essential elements to a robust design education, for they provide the context for the history, challenges and changes of the field. This thesis proposes a Design and Architecture High School in downtown Washington, a design developed through careful consideration of the elements essential to the transfer of knowledge.