Complex sentence: The timber circle was oriented towards the rising sun on the midwinter solstice, opposing the solar alignments at Stonehenge, whilst the avenue was aligned with the setting sun on the summer solstice and led from the river to the timber circle.
Split into simpler sentences: The timber circle was oriented towards the rising sun on the midwinter solstice, opposing the solar alignments at Stonehenge. The avenue was aligned with the setting sun on the summer solstice and led from the river to the timber circle.