so > thus

7 Beyond his croup, the length of all her lance,

croup > {Hinder end of saddle}

8 Till, sadly sousing on the sandy shore,

sadly > heavily; grievously sousing > falling (with weight or force)

9 He tumbled on a heap, and wallowed in his gore.

on > in

304.17

Like as the sacred Oxe, that carelesse stands,
2 With gilden hornes, and flowry girlonds crownd,
Proud of his dying honor and deare bands,
4 Whiles th'altars fume with frankincense arownd,
All suddenly with mortall stroke astownd,
6 Doth groueling fall, and with his streaming gore
Distaines the pillours, and the holy grownd,
8 And the faire flowres, that decked him afore;
So fell proud Marinell vpon the pretious shore.

1 Like the sacred ox, that careless stands,