Question: who formulated the principles describing the layers of sedimentary rocks
[{'answer': 'Walther', 'provenance': [{'wikipedia_id': '44412', 'title': 'Sedimentary rock', 'start_paragraph_id': 94, 'start_character': 567, 'end_paragraph_id': 94, 'end_character': 574, 'bleu_score': 1.0, 'section': 'Section::::Depositional environments.:Sedimentary facies.\n'}]}, {'provenance': [{'wikipedia_id': '44412', 'title': 'Sedimentary rock', 'start_paragraph_id': 94, 'start_character': 0, 'end_paragraph_id': 94, 'end_character': 580, 'bleu_score': 0.944714413050293, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17088855756605882607}, 'section': 'Section::::Depositional environments.:Sedimentary facies.\n'}]}]