| Ideally, an index fossil should be such as to guarantee that its presence in two separated rocks indicates their synchroneity. |
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| The synchroneity of horizon unifications and alternating regionalizations in Mesoamerica and the Andean region is striking and prompts the question of communication between these two areas of pre-Columbian high civilization. |
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| Artist and audience are bound together in a three-legged race, sometimes reluctant partners, sometimes joyful in synchroneity. |
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